WO2024038829A1 - α-FE-CONTAINING RARE EARTH ELEMENT-IRON-NITROGEN MAGNETIC POWDER, MANUFACTURING METHOD FOR SAME, MAGNETIC MATERIAL FOR MAGNETIC FIELD AMPLIFICATION, AND MAGNETIC MATERIAL FOR ULTRA-HIGH FREQUENCY ABSORPTION - Google Patents

α-FE-CONTAINING RARE EARTH ELEMENT-IRON-NITROGEN MAGNETIC POWDER, MANUFACTURING METHOD FOR SAME, MAGNETIC MATERIAL FOR MAGNETIC FIELD AMPLIFICATION, AND MAGNETIC MATERIAL FOR ULTRA-HIGH FREQUENCY ABSORPTION Download PDF

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WO2024038829A1
WO2024038829A1 PCT/JP2023/029295 JP2023029295W WO2024038829A1 WO 2024038829 A1 WO2024038829 A1 WO 2024038829A1 JP 2023029295 W JP2023029295 W JP 2023029295W WO 2024038829 A1 WO2024038829 A1 WO 2024038829A1
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rare earth
iron
magnetic powder
region
nitrogen
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PCT/JP2023/029295
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French (fr)
Japanese (ja)
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純 赤松
哲 阿部
伸嘉 今岡
将裕 阿部
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日亜化学工業株式会社
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/16—Metallic particles coated with a non-metal
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
    • B22F1/00—Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties
    • B22F1/17—Metallic particles coated with metal
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G49/00—Compounds of iron
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/02—Making ferrous alloys by powder metallurgy
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
    • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
    • H01F1/147—Alloys characterised by their composition
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
    • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
    • H01F1/20—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
    • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
    • H01F1/20—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder
    • H01F1/22—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together
    • H01F1/24—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together the particles being insulated
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F1/00—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties
    • H01F1/01—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials
    • H01F1/03—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity
    • H01F1/12—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials
    • H01F1/14—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys
    • H01F1/20—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder
    • H01F1/22—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together
    • H01F1/24—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together the particles being insulated
    • H01F1/26—Magnets or magnetic bodies characterised by the magnetic materials therefor; Selection of materials for their magnetic properties of inorganic materials characterised by their coercivity of soft-magnetic materials metals or alloys in the form of particles, e.g. powder pressed, sintered, or bound together the particles being insulated by macromolecular organic substances
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
    • H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
    • H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets

Definitions

  • the present disclosure relates to an ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder, a method for producing the same, a magnetic material for magnetic field amplification, and a magnetic material for absorbing ultra-high frequencies.
  • Patent Document 1 does not have sufficient efficiency to be applied as a magnetic field amplification material in the above-mentioned range of 1 MHz to 1 THz, and is not suitable for use as an ultra-wide frequency band absorbing material in the ultra-high frequency range.
  • the problem is that it does not have high frequency characteristics that meet the needs.
  • An object of the present disclosure is to provide a magnetic powder with excellent high frequency characteristics, which has low core loss and excellent efficiency even when high frequency is applied, and a method for manufacturing the same.
  • the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder includes rare earths R (R is Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, and a core region containing at least one member selected from the group consisting of Sm (if Sm is included, Sm is less than 50 atomic % with respect to the entire R component), Fe, and N;
  • R is Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu
  • R is Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu
  • R is Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu
  • a core region containing at least one member selected from the group consisting of Sm if Sm is included, Sm is less than 50 atomic % with respect to the entire R component
  • the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder includes rare earths R (R is Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu , and Sm (if Sm is included, Sm is less than 50 atomic % with respect to the entire R component), Fe, and N; Outside the region, it has a sea-island structure including a sea region and an island region, and the atomic concentration (%) of Fe is higher in the island region than in the sea region, and the atomic concentration (%) of rare earths R and O is The island region has a lower ⁇ -Fe content region than the sea region.
  • the method for producing ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder includes rare earth R (R is Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Rare earth-iron containing at least one member selected from the group consisting of Tm, Lu, and Sm (if Sm is included, Sm is less than 50 atomic % with respect to the entire R component), Fe, and N -
  • R is Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er
  • Fe and N -
  • a phosphorus treatment step to obtain a rare earth-iron-nitrogen magnetic powder having a phosphorus compound-coated portion, and a heat treatment of the rare-earth-iron-nitrogen magnetic powder having a phosphorus compound-coated portion at a temperature of 350° C. or more and 600° C. or less in an oxygen-containing atmosphere. This includes an oxidation step.
  • the results of XRD analysis of the magnetic powders produced in Examples 1 to 4 and Comparative Examples 1 to 3 are shown.
  • a STEM image and a STEM-EDX image near the surface of a cross section of the magnetic powder produced in Comparative Example 1 are shown.
  • the results of line analysis near the surface of a cross section of the magnetic powder produced in Comparative Example 1 are shown.
  • 1 shows a STEM image and a STEM-EDX image near the surface of a cross section of the magnetic powder produced in Example 1.
  • the results of line analysis near the surface of the cross section of the magnetic powder produced in Example 1 are shown.
  • a STEM image and a STEM-EDX image near the surface of a cross section of the magnetic powder produced in Example 2 are shown.
  • the results of line analysis near the surface of the cross section of the magnetic powder produced in Example 2 are shown.
  • a STEM image of the entire ⁇ -Fe-containing region of the cross section of the magnetic powder produced in Example 2 is shown.
  • the results of line analysis of the entire ⁇ -Fe-containing region of the cross section of the magnetic powder produced in Example 2 are shown.
  • a STEM image and a STEM-EDX image of the vicinity of the surface of a cross section of the magnetic powder produced in Example 4 are shown.
  • the results of line analysis near the surface of the cross section of the magnetic powder produced in Example 4 are shown.
  • a STEM-EDX image of the entire ⁇ -Fe-containing region of the cross section of the magnetic powder produced in Example 4 is shown.
  • the line analysis results of the entire ⁇ -Fe-containing region of the cross section of the magnetic powder produced in Example 4 are shown.
  • a TEM image and an electron diffraction image of the entire ⁇ -Fe-containing region of a cross section of the magnetic powder produced in Example 4 are shown.
  • the frequency dependence of the complex relative magnetic permeability of magnetic materials using magnetic powders produced in Examples 1 to 4 and Comparative Examples 1 to 3 is shown.
  • An enlarged view of the vicinity of the surface of the cross section of the magnetic powder of Example 1 shown in FIG. 3A is shown.
  • the frequency dependence of the complex relative magnetic permeability of the magnetic material using the magnetic powder produced in Example 6 is shown.
  • high frequency refers to electromagnetic waves having a high frequency
  • in this disclosure unless otherwise specified, it specifically refers to electromagnetic waves of 1 MHz or more and less than 1 GHz.
  • super high frequency refers to electromagnetic waves having a frequency of 1 GHz or more and 1 THz or less, which is higher than “high frequency”.
  • an increase in the value of ⁇ (a decrease in the values of tan ⁇ and ⁇ ) is referred to as "an improvement in ⁇ (tan ⁇ )"; on the other hand, an increase in the value of ⁇ (an increase in the values of tan ⁇ and ⁇ ) ) is said to be “deterioration of ⁇ (tan ⁇ )" in the magnetic field amplification characteristics.
  • magnetic field amplification property means that the real term ( ⁇ ') of the complex relative magnetic permeability of the magnetic material is larger than 1, which is the real term of the relative magnetic permeability of a vacuum, and the property of the space in which the magnetic material is placed is A property that increases the magnetic field compared to a vacuum (or atmosphere).
  • Good or high magnetic field amplification characteristics means that ⁇ ' is high, and a material with ⁇ ' exceeding 2 at a certain frequency f is referred to as a "magnetic material for magnetic field amplification" (at frequency f).
  • relative magnetic permeability it is a general term for the absolute value of the real term and the absolute value of the imaginary term of complex relative magnetic permeability.
  • High relative magnetic permeability means that the real term of relative magnetic permeability is high unless otherwise specified.
  • the "ultra-high frequency absorption” property refers to the absorption property in the super-high frequency region, and in the super-high frequency region, the imaginary term ( ⁇ '') of the complex relative magnetic permeability of the magnetic material is larger than 0, and the magnetic material It is a property of attenuating high frequency waves incident on a space in which a material is placed. Good or high super high frequency absorption property at a certain frequency f means that ⁇ '' is high at that frequency f.
  • a material whose ⁇ '' exceeds 0 in the ultra-high frequency region is referred to as a "magnetic material for ultra-high frequency absorption.”
  • a change in ⁇ '' is also referred to as “improving ⁇ ”
  • a decrease in ⁇ '' is also referred to as “deterioration in ⁇ ”.
  • the magnetic field amplification characteristics in the high frequency region and the absorption characteristics in the ultra-high frequency region are collectively referred to as "high frequency characteristics.”
  • the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder of the present embodiment has rare earth elements R (R is composed of Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Sm).
  • R is composed of Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Sm).
  • the core region is made of rare earth-iron-nitrogen powder, specifically rare earth R (R is made of Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Sm). At least one selected from the group consisting of Sm (if Sm is included, Sm is less than 50 atomic % with respect to the entire R component), Fe, and N.
  • R is made of Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Sm.
  • Sm At least one selected from the group consisting of Sm (if Sm is included, Sm is less than 50 atomic % with respect to the entire R component), Fe, and N.
  • the core region has a crystal structure of Th 2 Zn 17 type or Th 2 Ni 17 type, and has a general formula of R x Fe 100-xy N y (where R is Y, Ce, Pr, At least one selected from Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Sm, and when Sm is included, Sm is less than 50 atomic % with respect to the entire R component. It may be a nitride consisting of iron (Fe), nitrogen (N), iron (Fe), and nitrogen (N).
  • x is 3 or more and 30 or less
  • y is 10 or more and 30 or less
  • the remainder is mainly Fe.
  • the Sm content is less than 50 atom %, preferably 25 atom % or less, and more preferably 5 atom % or less, based on the entire R component.
  • the method for manufacturing the rare earth-iron-nitrogen magnetic powder constituting the core region is not particularly limited, and examples of the manufacturing method will be described in detail below.
  • the method for producing rare earth-iron-nitrogen magnetic powder using the solid phase method is as follows: A step of mixing R oxide powder, Fe raw material, and Ca powder (mixing step), a step of reducing the obtained mixture (reduction step); Process of nitriding the alloy particles obtained in the reduction process (nitriding process) This is a method that includes
  • alloy particles are obtained by mixing rare earth R oxide powder, Fe raw material, and Ca powder.
  • Fe raw material not only metal Fe but also Fe 2 O 3 and/or Fe 3 O 4 can be used as the Fe raw material.
  • Content when using Fe 2 O 3 and/or Fe 3 O 4 Fe 2 O 3 and/or relative to the total number of moles of Fe contained in metal Fe, Fe 2 O 3 and/or Fe 3 O 4
  • the total number of moles of Fe contained in Fe 3 O 4 is preferably 30 atomic % or less. Due to the heat of reaction when these iron oxides are reduced by Ca, the reaction progresses uniformly as a whole, leading to saving of external energy and improvement of yield.
  • the amount of granular Ca mixed needs to be sufficient to reduce the oxide of the R oxide and the metal oxide to be selectively mixed.
  • the amount of granular Ca to be mixed is 0.5 times or more and 3 times or less relative to the equivalent amount of oxygen atoms contained in the R oxide and Fe 2 O 3 and/or Fe 3 O 4 to be selectively mixed. It may be 1 time or more and 2 times or less is preferable.
  • the mixed powder obtained in the mixing step is placed in a heating container that can be evacuated. After evacuating the inside of the heating container, it is heated at 600° C. or higher and 1300° C. or lower, preferably 700° C. or higher and 1200° C. or lower, more preferably 800° C. or higher and 1100° C. or lower, while passing argon gas. If the heating temperature is less than 600°C, the reduction reaction of the oxide will not proceed, and if the heating temperature exceeds 1300°C, the rare earth and Fe may melt and form lumps.
  • the heat treatment time may be 4 hours or less, preferably less than 120 minutes, and more preferably less than 90 minutes, and the lower limit of the heat treatment time is preferably 10 minutes or more, and 30 minutes or more. More preferred.
  • the mixed powder contains an appropriate amount of Fe 2 O 3 and/or Fe 3 O 4 in addition to metal Fe, self-heating occurs during the temperature rise, and the reaction progresses efficiently and uniformly.
  • the particle size of the obtained rare earth-iron-nitrogen magnetic powder can be controlled. Generally, as the reduction temperature increases, the powder particle size increases.
  • the nitriding step is a step of nitriding the alloy particles obtained in the reduction step. It is cooled in an argon gas to a temperature range of preferably 250°C or more and 800°C or less, more preferably 300°C or more and 600°C or less. In order to suppress the decomposition of the nitriding reactants in the subsequent nitriding step and increase reaction efficiency, the temperature is preferably cooled to a temperature range of 400° C. or higher and 550° C. or lower. Thereafter, after the heating container is evacuated again, nitrogen gas is introduced. The gas to be introduced is not limited to nitrogen, but may be a gas containing nitrogen atoms, such as ammonia. After heating for several hours, preferably about 5 hours at a pressure higher than atmospheric pressure while passing nitrogen gas, the heating is stopped and allowed to cool.
  • the product obtained after the nitriding process contains by-product CaO, unreacted metallic calcium, etc. in addition to rare earth-iron-nitrogen magnetic powder, and is in the form of a composite sintered mass.
  • this product is poured into ion-exchanged water, and calcium oxide (CaO) and other calcium-containing components are converted into a calcium hydroxide (Ca(OH) 2 ) suspension into magnetic powder.
  • CaO calcium oxide
  • Ca(OH) 2 calcium hydroxide
  • stirring in water, standing still, and removal of the supernatant liquid may be repeated several times.
  • residual calcium hydroxide may be sufficiently removed by washing the magnetic powder with acetic acid or the like.
  • the rare earth-iron-nitrogen magnetic powder thus obtained tends to have a sharper particle size distribution.
  • the method for producing rare earth-iron-nitrogen magnetic powder by precipitation method is as follows: A step of mixing a solution containing R and Fe with a precipitant to obtain a precipitate containing R and Fe (precipitation step); a step of calcining the precipitate to obtain an oxide containing R and Fe (oxidation step); a step of heat-treating the oxide in an atmosphere containing a reducing gas to obtain a partial oxide (pretreatment step); A process of reducing the partial oxide (reduction process) and a process of nitriding the alloy particles obtained in the reduction process (nitriding process) This is a method that includes
  • a solution containing R and Fe is prepared by dissolving an R raw material containing a rare earth element R and an Fe raw material containing iron Fe in a strongly acidic solution.
  • the R raw material and Fe raw material are not limited as long as they can be dissolved in a strongly acidic solution.
  • R oxide may be used as the R raw material
  • iron sulfate (FeSO 4 ) may be used as the Fe raw material.
  • concentration of the solution containing R and Fe can be adjusted as appropriate within a range where the R raw material and Fe raw material are substantially dissolved in the acidic solution.
  • acidic solutions include sulfuric acid in terms of solubility.
  • the solution containing R and Fe only needs to be a solution containing R and Fe at the time of reaction with the precipitant.
  • the raw material containing R and the raw material containing Fe are prepared as separate solutions, and each The solution may be added dropwise to react with the precipitant. Even in the case of preparing separate solutions, each raw material is appropriately adjusted within the range that it is substantially dissolved in the acidic solution.
  • the precipitant is not limited as long as it reacts with an alkaline solution containing R and Fe to form a precipitate, and examples thereof include aqueous ammonia and caustic soda, with caustic soda being preferred.
  • the precipitate After separating the precipitate, the precipitate is redissolved in the remaining solvent during the heat treatment in the subsequent oxidation process, and when the solvent evaporates, the precipitate may aggregate or the particle size distribution, powder particle size, etc. may change. In order to prevent the separation from occurring, it is preferable to remove the solvent from the separated product.
  • a method for removing the solvent when using water as a solvent, for example, a method of drying in an oven at 70° C. or higher and 200° C. or lower for 5 hours or more and 12 hours or less can be mentioned.
  • a step of separating and washing the obtained precipitate may be included.
  • the washing step is carried out as appropriate until the conductivity of the supernatant solution becomes 5 mS/m or less.
  • a solvent preferably water
  • a filtration method, a decantation method, etc. can be used as the step of separating the precipitate.
  • the oxidation step is a step of obtaining an oxide containing R and Fe by firing the precipitate formed in the precipitation step.
  • heat treatment can convert the precipitate into an oxide.
  • heat-treating the precipitate it needs to be carried out in the presence of oxygen, and can be carried out, for example, under an atmospheric atmosphere.
  • the nonmetallic portion of the precipitate contains oxygen atoms.
  • the heat treatment temperature in the oxidation step (hereinafter referred to as oxidation temperature) is not particularly limited, but is preferably 700°C or more and 1300°C or less, more preferably 900°C or more and 1200°C or less.
  • the heat treatment time is also not particularly limited, but may be 0.5 hours or more and 4 hours or less, preferably 1 hour or more and 3 hours or less.
  • the pretreatment step is a step of heat-treating an oxide containing R and Fe in an atmosphere containing a reducing gas to obtain a partial oxide in which a portion of the oxide is reduced.
  • the reduction step refers to heating the partial oxide at a temperature of 600°C or more and 1300°C or less, preferably 700°C or more and 1200°C or less, more preferably 800°C or more and 1100°C or less, in the presence of a reducing agent to reduce the alloy particles. This is the process of obtaining If the heating temperature is less than 600°C, the reduction reaction of the oxide will not proceed, and if the heating temperature exceeds 1300°C, R and Fe may melt and form a lump. In addition, when the heating temperature is 700°C or higher, the reduction time can be shortened and productivity tends to improve.
  • the heating temperature is 1200°C or lower
  • the scattering of Ca which is a reducing agent
  • the reduction time can be reduced.
  • the particle size of the rare earth-iron-nitrogen magnetic powder can be controlled, and generally, the higher the reduction temperature, the larger the powder particle size.
  • the heat treatment time is preferably less than 120 minutes, more preferably less than 90 minutes, and the lower limit of the heat treatment time is preferably 10 minutes or more, and more preferably 30 minutes or more.
  • the nitriding process is a process of obtaining anisotropic magnetic powder by nitriding the alloy particles obtained in the reduction process. Since the particulate precipitate obtained in the above-mentioned precipitation step is used, porous massive alloy particles can be obtained in the reduction step. As a result, nitriding can be performed immediately by heat treatment in a nitrogen atmosphere without performing a pulverization process, so that nitriding can be performed uniformly.
  • the heat treatment temperature (hereinafter referred to as nitriding temperature) in the nitriding treatment of the alloy particles is preferably 250°C or more and 800°C or less, more preferably 300°C or more and 600°C or less.
  • the temperature is particularly preferably set to 400°C or more and 550°C or less, and the atmosphere is replaced with a nitrogen atmosphere within this temperature range. be exposed.
  • the heat treatment time may be set to such an extent that the alloy particles are sufficiently uniformly nitrided.
  • the ⁇ -Fe containing region is present outside the core region.
  • the ⁇ -Fe-containing region contains ⁇ -Fe and at least one selected from the group consisting of rare earth R oxides, nitrides, and oxynitrides.
  • the ⁇ -Fe-containing region contains an oxide or oxynitride of rare earth R.
  • the oxide, nitride, and oxynitride of the rare earth R are neodymium oxide, neodymium nitride, and neodymium oxynitride, respectively, when the rare earth R is Nd, for example.
  • the ⁇ -Fe-containing region improves the insulation between adjacent magnetic particles and reduces iron loss caused by eddy currents that cross between grains, thereby further improving tan ⁇ and phase angle ⁇ in the high frequency region, resulting in higher efficiency.
  • a magnetic material for magnetic field amplification is obtained.
  • the ⁇ -Fe-containing region may further contain a double oxide, a double nitride, a double oxynitride, or the like containing rare earth R and iron, to the extent that magnetic coupling is not impaired. These double oxides, double nitrides, and double oxynitrides may have a perovskite structure or a spinel structure.
  • the ⁇ -Fe-containing region magnetically connects adjacent magnetic particles and reduces the demagnetizing field, thereby tending to further improve the real number term ⁇ ' of magnetic permeability of the magnetic material for magnetic field amplification.
  • the ⁇ -Fe-containing region preferably includes nanocrystals made of at least one selected from the group consisting of rare earth R oxides, nitrides, and oxynitrides, and nanocrystals made of ⁇ -Fe. It is thought that by including these nanocrystals, the effects of electrical insulation and magnetic coupling become greater.
  • Electrical insulation here refers to the presence of ⁇ -Fe-containing regions with high electrical resistance on the surface of the magnetic powder, which blocks electrical conduction between the core regions of adjacent magnetic particles. This refers to preventing the generation of eddy currents that cross between core regions.
  • magnetic coupling here refers to the presence of ⁇ -Fe-containing regions, which have high electrical resistance but ferromagnetism, on the surface of the magnetic powder, resulting in ferromagnetic coupling and static electricity between adjacent core regions. Refers to creating magnetic coupling. This magnetic coupling reduces the local demagnetizing field and achieves high relative permeability because the demagnetizing field acting on the core region is weakened.
  • the ⁇ -Fe-containing region is preferably present as an ⁇ -Fe-containing region layer outside the core region.
  • the nanocrystals made of at least one selected from the group consisting of oxides, nitrides, and oxynitrides of rare earth R contained in the ⁇ -Fe-containing region preferably have an average particle size of 1 nm or more and less than 1000 nm. , more preferably 1 nm or more and 100 nm or less, even more preferably 1 nm or more and 20 nm or less, particularly preferably 1 nm or more and 10 nm or less.
  • the average particle diameter of the ⁇ -Fe nanocrystals is preferably 1 nm or more and less than 1000 nm, more preferably 1 nm or more and 100 nm or less, even more preferably 1 nm or more and 20 nm or less, and 1 nm or more and 10 nm or less. It is particularly preferable that there be.
  • the particle size of these nanocrystals can be determined by TEM (transmission electron microscopy), STEM (scanning transmission electron microscopy), or EDX (energy dispersive X-ray analysis).
  • the atomic concentration (atomic %) of Fe in the entire ⁇ -Fe containing region is preferably 25% or more, more preferably 50% or more.
  • the upper limit of the Fe atomic concentration is not particularly limited, but may be 80% or less.
  • the atomic concentration (atomic %) of rare earth R in the entire ⁇ -Fe containing region is preferably 2% or more and 50% or less, more preferably 5% or more and 30% or less.
  • the atomic concentration (atomic %) of nitrogen in the entire ⁇ -Fe containing region is preferably 0% or more and 50% or less, more preferably 0.01% or more and 30% or less.
  • the atomic concentration (atomic %) of oxygen in the entire ⁇ -Fe containing region is preferably 0% or more and 55% or less, more preferably 0.01% or more and 30% or less.
  • the atomic concentration of each element in the ⁇ -Fe containing region is determined by averaging the atomic concentration in each region in STEM-EDX line analysis.
  • the average atomic concentration (atomic %) of O in the entire ⁇ -Fe-containing region is preferably higher than the average atomic concentration (atomic %) of O in the core region.
  • the average atomic concentration of O in the ⁇ -Fe-containing region is preferably 1.05 times or more, more preferably 1.5 times or more, even more preferably 2 times or more, as the average atomic concentration of O in the core region. Particularly preferred is 4 times or more.
  • the average atomic concentration of R in the ⁇ -Fe-containing region is at most twice the average atomic concentration of R in the core region, preferably at most 1.9 times, and more preferably at most 1.8 times.
  • the average atomic concentration of R in the ⁇ -Fe containing region may be 0.1 times or more, preferably 0.5 times or more, the average atomic concentration of R in the core region.
  • the "average atomic concentration" of a specific element refers to one or more particles that penetrate in the thickness direction from the core region to the outermost surface of the ⁇ -Fe-containing region in the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder.
  • STEM-EDX line analysis is performed on the line segment to obtain measured values of the atomic concentration of element X at 50 or more points, and the atomic concentration is the average of these measurements.
  • the thickness of the ⁇ -Fe-containing region is preferably 0.01% or more and less than 50%, and 0.01% or more and 45% or less of the average particle size of the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder. It is more preferably at least 0.01% and at most 35%, particularly preferably at least 0.5% and at most 20%. When the content is 0.001% or more, electrical insulation tends to improve. If it is less than 50%, ⁇ ' tends to increase due to the presence of the core region containing rare earth elements R, Fe, and N.
  • the thickness of the ⁇ -Fe containing region is preferably 1 nm or more and 10 ⁇ m or less, more preferably 10 nm or more and 5 ⁇ m or less. Further, from the viewpoint of improving ⁇ ' in the high frequency region, the thickness is more preferably 50 nm or more and 1 ⁇ m or less. Electrical insulation tends to improve when the thickness is 1 nm or more. If it is 10 ⁇ m or less, ⁇ ' tends to increase due to the presence of the core region.
  • the thickness of the ⁇ -Fe-containing region is determined by the line in the TEM, STEM, or FE-SEM observation image of the cross section of the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder. It can be measured by performing compositional analysis by analysis or surface analysis, or point analysis using a sufficient number of measurement points.
  • the surface coverage of the core region by the ⁇ -Fe containing region is preferably 10% or more, more preferably 50% or more, even more preferably 80% or more, and particularly preferably 100%.
  • Increasing the surface coverage of the core region has the effect of increasing electrical insulation and improving tan ⁇ and phase angle ⁇ . Especially when the surface coverage is 100%, electrical isolation of the magnetic powder is further promoted. , the above effects can be further enhanced.
  • the surface coverage of the core region by the ⁇ -Fe-containing region can be measured by observing a cross section of the powder using a TEM, STEM, or FE-SEM equipped with EDX.
  • the ratio of the length of the contact portion between the ⁇ -Fe-containing region and the core region to the length is defined as “surface coverage”. At this time, it is preferable to measure the cross sections of 20 to 50 magnetic powders from among the images observed by the above-mentioned method, and take the average value as the surface coverage.
  • the core region contains a rare earth-iron-nitrogen compound, and in the XRD diffraction pattern, the diffraction peak intensity (I) of the (110) plane of ⁇ -Fe and the core
  • the ratio (I)/(II) to the peak intensity (II) of the strongest line of the rare earth-iron-nitrogen compound in the region is preferably 0.01 or more and less than 10, and preferably 0.02 or more and less than 5. is more preferable, and even more preferably 0.1 or more and 2 or less.
  • the diffraction peak intensity (I) of the (110) plane of ⁇ -Fe represents the amount of ⁇ -Fe present, and when the ratio (I)/(II) mentioned above is 0.01 or more and less than 10, There is a tendency to achieve both magnetic coupling and electrical insulation between magnetic particles.
  • the ratio (I)/(II) is 0.01 or more, having an ⁇ -Fe separated phase with a specific thickness tends to improve electrical insulation and increase ⁇ '.
  • the ratio (I)/(II) is less than 10 the electrical insulation is improved and the volume fraction of the core region is also increased, so ⁇ ' tends to become large.
  • the diffraction peak intensity in the XRD diffraction pattern is measured using a powder X-ray crystal diffractometer, and the diffraction peak intensity of the (110) plane of ⁇ -Fe is the rare earth-iron-nitrogen system constituting the core region. It is calculated by dividing by the peak intensity of the strongest line of the compound.
  • the strongest line of rare earth-iron-nitrogen compounds is the (303) plane in the case of Th 2 Zn 17 type crystal (rhombohedral system), and the strongest line in the case of Th 2 Ni 17 type crystal (hexagonal system). It is a (302) plane.
  • the ⁇ -Fe-containing region has a structure in which ferromagnetic ⁇ -Fe phase nanocrystals are isolated in the R oxynitride phase, a so-called sea (R oxynitride phase)-island (nano ⁇ -Fe phase). It may have a structure.
  • R oxynitride a substance selected from the group consisting of ⁇ -Fe and rare earth R oxides, nitrides, and oxynitrides is referred to as R oxynitride.
  • each ⁇ -Fe metal phase is in the “sea” R oxynitride matrix phase. Since it is isolated, no electron percolation occurs and electrical insulation is maintained. Further, the ⁇ -Fe phase in the ⁇ -Fe containing region may be regularly arranged.
  • the ⁇ -Fe phase in the ⁇ -Fe-containing region is regularly arranged, it becomes possible for the ⁇ -Fe phase to be composed of nanocrystalline particles and to be arranged regularly with high density, and each The ⁇ -Fe phase of the ⁇ -Fe phase is ferromagnetically or magnetostatically coupled, and magnetic flux tends to pass through the ⁇ -Fe-containing region more easily, thereby making the magnetic bond more stable.
  • the ⁇ -Fe containing region has a sea-island structure including a sea region and an island region, and the atomic concentration (%) of Fe is higher in the island region than in the sea region, and the atomic concentration of rare earths R and O is higher in the island region than in the sea region. (%) may have a lower structure in the island region than in the sea region.
  • the Fe atomic concentration (%) in the island region is preferably 10 points or more higher than the Fe atomic concentration (%) in the sea region, and more preferably 20 points or more higher.
  • the atomic concentration (%) of rare earths R and O in the sea region is preferably 2 points or more higher, and more preferably 5 points or more higher than the atomic concentration (%) of rare earths R and O in the island region.
  • the atomic concentration (%) of each element in the island region and the sea region is determined by averaging the atomic concentration in each region in STEM-EDX line analysis.
  • the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder may have the following characteristics when measured by XRD.
  • ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder has a lattice matching between ⁇ -Fe phase and R oxynitride phase, so the ⁇ -Fe(110) plane diffraction peak intensity contains R oxynitride.
  • the size of the oriented crystal phase is preferably 1 to 100%, more preferably 10 to 100%, of the film thickness of the ⁇ -Fe-containing region. When it is less than 1%, the effect of magnetic coupling becomes small.
  • the larger the volume fraction of the oriented region to the ⁇ -Fe-containing region is, the better, preferably 1 to 100%, more preferably 10 to 100%.
  • the enhancement effect of magnetic coupling may become larger than that without orientation.
  • the presence or absence of an oriented crystal phase, its size, and volume fraction can be determined by observing a STEM image of ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder or using an ED (electron diffraction) device attached to a TEM device. It can be measured by For example, in a cross-sectional STEM photograph of an ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder, a region containing both an ⁇ -Fe phase and an R oxynitride phase and having lattice fringes in one direction is considered to be ⁇ oriented.'' Image analysis is performed as "area".
  • the region including the ⁇ -Fe-containing region of ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder if the ⁇ -Fe-containing region is thick, it can be divided into multiple fields of view.
  • the size and volume fraction of the oriented crystal phase can be confirmed by photographing five locations of the oriented crystal phase and comparing the "oriented region" and the non-oriented region among the photographed regions. Further, the presence or absence of oriented crystals can be confirmed by the electron beam diffraction pattern of the STEM-ED image.
  • the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder preferably further has a phosphorus compound coating.
  • the phosphorus compound coating portion is preferably present outside the ⁇ -Fe-containing region, that is, on the opposite side of the core region across the ⁇ -Fe-containing region.
  • the thickness of the phosphorus compound coating part is preferably 1 nm or more and 200 nm or less, more preferably 2 nm or more and 50 nm or less, from the viewpoint of improving the tan ⁇ and phase angle ⁇ of the magnetic material in the high frequency region and ⁇ '' in the ultra-high frequency region.
  • the thickness of the coating part is determined by line analysis or surface analysis using EDX on a cross section of the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder in a TEM, STEM, or FE-SEM observation image, and a sufficient number of measurement points.
  • the range where the atomic concentration of phosphorus (P) is observed as 1 atomic% or more may be regarded as the phosphorus compound coating area.
  • An example is a structure in which the phosphorus compound coating part completely covers the surface of ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder (surface coverage rate 100%).In this case, adjacent magnetic particles It is considered to be in a completely electrically insulated state.
  • the phosphorus compound coating has the effect of reducing iron loss due to eddy currents that cross between grains, and the tan ⁇ and A magnetic material for magnetic field amplification with higher phase angle ⁇ and higher efficiency can be obtained.
  • the influence of eddy current can be reduced even in the ultra-high frequency region, and a magnetic material for ultra-high frequency absorption that maintains higher ultra-high frequency absorption characteristics can be obtained.
  • the phosphorus compound coating part does not have to completely cover the surface of the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder, but as long as the surface coverage is 10% or more, A certain degree of eddy current reduction effect can be expected.
  • a surface coverage of preferably 50% or more, more preferably 80% or more is desired. If the surface coverage is 10% or more and less than 80%, the free phosphorus compound will be absorbed by the magnetic powder. It is preferable that the magnetic powder be present between the particles.
  • the surface coverage rate of the phosphorus compound coating part of the magnetic powder can be estimated by observing the cross section of the powder with a TEM, STEM, or FE-SEM equipped with EDX.
  • the ratio of the length of the contact portion of the phosphorus-containing film to the total circumference of the surface of the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder that is formed and observed is defined as "surface coverage.” At this time, it is preferable to measure the cross sections of 20 to 50 magnetic powders from among the images observed by the above-mentioned method, and take the average value as the surface coverage.
  • the phosphorus compounds constituting the phosphorus compound coating include inorganic phosphoric acids such as orthophosphoric acid, pyrophosphoric acid, and polyphosphoric acid, and inorganic phosphoric acids such as Na, Ca, Pb, Zn, Fe, R, ammonium, Mo, W, V, Selected from phosphoric acid compounds such as phosphates with Cr (these metal elements and atomic groups are referred to as M components in this disclosure, and may be simply written as M), R, Fe, M, and N.
  • Examples include "phosphorus-containing amorphous compounds” and "phosphorus-containing nanocrystalline compounds” that contain at least one type of P and/or phosphorus-containing substances.
  • phosphates, ⁇ phosphorus-containing amorphous compounds'' and ⁇ phosphorus-containing nanocrystalline compounds'' are particularly effective in making the surface coating of the powder consisting of the core region and ⁇ -Fe-containing region dense.
  • the above-mentioned "phosphorus-containing nanocrystal-containing material" is a rare earth phosphate, or is in a eutectic or mixed crystal state containing at least one of iron phosphate and phosphate M and a rare earth phosphate. It's okay.
  • Containing a "phosphorus-containing nanocrystalline compound” further improves thermal stability, so even if high heat is applied during the production of bonded magnetic materials after phosphorus treatment, such as kneading and thermosetting processes, the high-frequency properties of the magnetic powder will deteriorate. It also contributes to the high thermal stability and excellent efficiency of the final molded product.
  • nanocrystals refer to fine crystals of 1 nm or more and less than 1 ⁇ m, and phosphorus compounds containing fine crystals of less than 1 nm are in the category of amorphous compounds.
  • the crystallinity of the phosphorus compound coated portion and the diameter of fine crystals in the phosphorus compound coated portion can be confirmed by lattice image observation using the TEM method and analysis using an ED (electron diffraction) device attached to the TEM device.
  • the content of the phosphorus compound in the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder is preferably 0.5% by mass or more and 4.5% by mass or less, and 0.55% by mass or more and 2.5% by mass or less. More preferably, 0.75% by mass or more and 2% by mass or less is most preferred. If it is 4.5% by mass or less, it may be possible to reduce the aggregation of rare earth-iron-nitrogen magnetic powder, suppressing the decrease in relative magnetic permeability, and at the same time reducing the deterioration of tan ⁇ and phase angle ⁇ in the high frequency region. There is a tendency to do so.
  • the electrical insulation of the phosphorus compound coating is further improved, which also suppresses a decrease in relative magnetic permeability and prevents deterioration of tan ⁇ and phase angle ⁇ in the high frequency region. There is a tendency that it can be reduced.
  • the content of the phosphorus (P) element in the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder is preferably 0.02% by mass or more, more preferably 0.05% by mass or more, and 0.15% by mass. The above is more preferable.
  • the phosphorus content in the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder is preferably 4% by mass or less, more preferably 2% by mass or less, and even more preferably 1% by mass or less.
  • the phosphorus compound coats at least a portion of the surface of the powder consisting of the core region and the ⁇ -Fe-containing region in that it does not reduce efficiency due to eddy currents, that is, it does not cause deterioration of tan ⁇ or phase angle ⁇ .
  • a surface coverage of 10% or more is effective in reducing eddy current to some extent, but a surface coverage of 50% or more, more preferably 80% or more is desired.
  • a surface coverage of 10% or more tends to suppress eddy currents generated between grains and reduce deterioration of tan ⁇ and phase angle ⁇ .
  • the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder with a coverage rate of 100% Due to the phosphorus compound coating, the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder with a coverage rate of 100% has extremely deteriorated tan ⁇ and phase angle ⁇ , and the composition, crystal structure, and powder grains of the magnetic powder deteriorate. Although it depends on the diameter, tan ⁇ of 0.01 or less and high ⁇ can be achieved at 2 MHz.
  • the phosphorus compound is effective in at least one part of the powder consisting of the core region and the ⁇ -Fe-containing region, in that it does not cause a decrease in relative magnetic permeability due to eddy currents, especially a decrease in ⁇ '', that is, a deterioration in ultra-high frequency absorption characteristics. It is preferable that the surface of the part is covered.A surface coverage of 10% or more has the effect of reducing eddy current to some extent, but preferably a surface coverage of 50% or more, more preferably 80% or more. If the surface coverage is less than 10%, eddy currents generated between grains cannot be sufficiently prevented, and ⁇ '' tends to decrease due to the skin effect.
  • ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder with a coverage rate of 100% Due to the phosphorus compound coating, ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder with a coverage rate of 100% has an extremely small decrease in relative permeability due to eddy current, and the composition, crystal structure and Depending on the powder particle size, etc., it is possible to achieve ⁇ '' of 1 or more at 1 GHz.
  • the phosphorus compound coating portion existing on the surface of the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder has a rare earth (R) atomic concentration that is higher than that of the rare earth-iron-nitrogen magnetic powder (core region), which is the base material. may have a region (R high concentration region) where the R atom concentration is higher than the R atom concentration.
  • the R atom concentration in the R high concentration region can be 1.05 times or more than the R atom concentration in the core region, preferably 1.1 times or more, more preferably 1.2 times or more, and 1.5 times or more. More preferably, it is twice or more. Further, the R atom concentration in the R high concentration region can be, for example, four times or less than the R atom concentration in the core region.
  • the R high concentration region is a region including a layer showing the maximum peak of P (phosphorus) in STEM-EDX line analysis of ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder.
  • the thickness of the R high concentration region can be, for example, 1 nm or more, preferably 3 nm or more and 150 nm or less, and more preferably 5 nm or more and 100 nm or less.
  • the atomic concentration (atomic %) of each element in the R high concentration region is determined by averaging the atomic concentration in the phosphorus compound coating part in STEM-EDX line analysis.
  • the rare earth element may be, for example, Nd, and in that case, the Nd atomic concentration can be evaluated as a high Nd concentration region.
  • the R atom concentration in the R high concentration region may be 0.3 times or more, preferably 1 times or more, the Fe atom concentration in the R high concentration region.
  • the R atom concentration in the R high concentration region is preferably 20 times or less than the Fe atom concentration in the R high concentration region.
  • the atomic concentration ratio R/Fe of R and Fe in the R high concentration region may be 0.3 or more, preferably 0.5 or more, and more preferably 1 or more.
  • the upper limit of R/Fe in the R high concentration region may be 100 or less, or may be 10 or less.
  • R/Fe in the R high concentration region may have a higher value than R/Fe in the core region.
  • R/Fe in the R high concentration region can be 1 times or more the R/Fe in the core region, preferably 1.5 times or more, more preferably 2 times or more, and even more preferably 5 times or more.
  • the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder may further have a Mo high concentration layer.
  • Mo used when forming the phosphorus compound coating is present at a higher concentration than in the iron oxide layer and the ⁇ -Fe containing region.
  • the Mo high concentration layer is preferably present outside the ⁇ -Fe containing region. In some cases, having a Mo high concentration layer has the effect of increasing the strength of the coating layer and improving corrosion resistance.
  • the thickness of the Mo high-concentration layer is 0 It is preferably .01% or more and 10% or less, more preferably 0.02% or more and 1% or less. Further, the thickness of the Mo high concentration layer is preferably 1 nm or more and 1 ⁇ m or less, and more preferably 2 nm or more and 100 nm or less.
  • the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder may further have an iron oxide layer.
  • the iron oxide layer has iron oxide containing Fe 2 O 3 as a main component.
  • the iron oxide layer is preferably present outside the ⁇ -Fe-containing region, more preferably outside the phosphorus compound coating, and even more preferably outside the Mo high concentration layer. Having the iron oxide layer has the effect of providing thermodynamic stability to the ⁇ -Fe-containing region and increasing electrical insulation.
  • the thickness of the iron oxide layer is less than 0% of the average particle size of the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder. It is preferably 20% or less, and more preferably 0.001% or more and 5% or less. There is a tendency that a decrease in ⁇ ' can be suppressed by setting it to 20% or less. Further, the thickness of the iron oxide layer is preferably greater than 0 nm and less than or equal to 1 ⁇ m, and more preferably greater than or equal to 1 nm and less than or equal to 100 nm. There is a tendency that a decrease in ⁇ ' can be suppressed by setting the thickness of the iron oxide layer to 1 ⁇ m or less.
  • the average particle size of the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder is preferably 0.1 ⁇ m or more and 100 ⁇ m or less.
  • the magnetic material for magnetic field amplification preferably has a thickness of 1 ⁇ m or more and 100 ⁇ m or less.
  • the magnetic material for ultra-high frequency absorption preferably has a thickness of 0.1 ⁇ m or more and 10 ⁇ m or less.
  • a more preferable particle size range is 3 ⁇ m or more and 100 ⁇ m or less for a magnetic material for magnetic field amplification, which will be described later, and 0.1 ⁇ m or more and 3 ⁇ m or less for a magnetic material for ultra-high frequency absorption.
  • the amount of magnetic powder packed in the compact becomes small, so there is a risk that the real term of relative magnetic permeability in the high frequency range and the imaginary term of the relative magnetic permeability in the ultrahigh frequency range decrease.
  • the specific surface area becomes even larger, so the volume fraction of the magnetic material portion with a high real term of relative magnetic permeability in the high frequency region and a high imaginary term of the relative magnetic permeability in the ultrahigh frequency region may become small. be.
  • the properties as a magnetic material tend to be extremely poor.
  • the average particle diameter of the magnetic powder of the present disclosure is expressed as D50, and D50 is the particle size distribution on a volume basis of the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder. This is the particle size at which the integrated value corresponds to 50%.
  • f 0 1 THz if it is 3 ⁇ m
  • f 0 1 GHz if it is 100 ⁇ m
  • f 0 1 MHz if it is 100 ⁇ m. Therefore, a core region of Fe-containing rare earth-iron-nitrogen magnetic powder having an upper limit of particle size around this range is preferable as the magnetic material for magnetic field amplification of the present disclosure.
  • the particle size becomes smaller, the amount of magnetic powder packed in the compact becomes smaller and the specific surface area becomes larger. If the diameter is 0.1 ⁇ m, the relative magnetic permeability will only decrease by about 50%, but if the particle size is 0.05 ⁇ m, the relative magnetic permeability will be about 6%.
  • the lower limit of the core region of rare earth-iron-nitrogen magnetic powder is around 0.1 ⁇ m, regardless of frequency. Because of the above trade-off, it is preferable to set the particle size range to be more suitable for the intended frequency band of the magnetic material.
  • the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder preferably has a real number term ( ⁇ ') of relative magnetic permeability at 10 MHz of 6 or more, more preferably 10 or more.
  • ⁇ ' real number term of relative magnetic permeability at 10 MHz of 6 or more
  • the relative magnetic permeability of ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder can be measured as follows. A magnetic material for evaluation with a thickness of 1 mm is prepared by mixing ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder with an epoxy resin so that the mass ratio of resin and magnetic powder is 3:97.
  • the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder has a ratio of ⁇ 1 / ⁇ 2 of 0.8 or more, where the phase angle at 100 MHz is ⁇ 1 and the phase angle at 2 MHz is ⁇ 2 . is preferable, and more preferably 0.9 or more. The closer ⁇ 1 / ⁇ 2 is to 0.8 and 1, the more the decrease in energy efficiency can be reduced even at high frequencies.
  • the phase angle ⁇ is the phase angle when ⁇ ' (real number term of complex relative magnetic permeability) and ⁇ '' (imaginary number term of complex relative magnetic permeability) are expressed on the complex plane, and is the phase angle in tan ⁇ defined above. is the phase angle ⁇ which is the complementary angle of ⁇ .
  • the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder preferably has a phase angle ⁇ of 85° or more (tan ⁇ of 0.0875 or less) at 13 MHz, and preferably 88° or more (tan ⁇ of 0.0349 or less). It is more preferable that When the phase angle ⁇ at 13 MHz is 85° or more, it is suitably used as an RFID antenna material.
  • the magnetic anisotropy of the core region of the Fe-containing rare earth-iron-nitrogen magnetic powder of this embodiment is an in-plane magnetocrystalline anisotropy in which the magnetic moment is more likely to be oriented in the c-plane direction than in the c-axis direction. Show your gender.
  • the fact that the magnetic powder of the present embodiment has this property allows it to maintain the real number term ⁇ ' of high relative magnetic permeability in the high frequency region, and further express the imaginary number term ⁇ ' of high relative magnetic permeability in the ultra-high frequency region.
  • the absolute value of the negative magnetocrystalline anisotropy energy in the magnetic powder of this embodiment is very large, and furthermore, the magnetic powder with this in-plane magnetocrystalline anisotropy is contained without orientation. Therefore, its natural resonance frequency is widely distributed within the range of 1 GHz to 1 THz.
  • the surface of the ferromagnetic powder is coated with a phosphorus compound or an ⁇ -Fe-containing region contained in the magnetic powder, or The presence of phosphorus compounds or iron oxide layers between particles can suppress the generation of eddy currents between grains.Furthermore, when the magnetic powder has a specific average particle size, the eddy currents within the grains can be suppressed.
  • the magnetic material for magnetic field amplification of this embodiment is characterized by containing ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder.
  • ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder By containing ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder, it has a high relative permeability with ⁇ ' of 2 or more in the range of 1 MHz or more and less than 1 GHz for magnetic field amplification, and has a high relative permeability of ⁇ ' of 2 or more in the range of 1 MHz or more and less than 1 GHz. It may also have excellent efficiency such that the phase angle ⁇ becomes higher.
  • the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder preferably has a particle size of 1 ⁇ m or more and 100 ⁇ m or less.
  • the reason for this is as described above, and when powder larger than 100 ⁇ m is used as a magnetic material for amplifying a magnetic field of 1 MHz or more, the relative magnetic permeability tends to decrease due to the skin effect. Furthermore, when using powder of 7 ⁇ m or more as a magnetic material for magnetic field amplification, a large pressure of 0.5 GPa or more is usually applied to increase the volume fraction, so the powder comes into contact with each other and causes a large eddy current loss. occurs, and the real number term of relative magnetic permeability decreases significantly.
  • the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder with a fine and moderately soft substance such as a phosphorus compound that is not hard like ferrite or transition metal oxides and not too soft like resin. It is preferable for the magnetic powder to be present between the grains, thereby suppressing the deterioration of the properties inherent in the magnetic powder, such as the relative magnetic permeability.
  • the magnetic material for magnetic field amplification is suitably used at a frequency of 1 MHz or more and less than 1 GHz, but at 1 GHz or more, it is also used as a magnetic material for ultra-high frequency absorption. Therefore, depending on the composition, particle size distribution, etc. of the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder, the imaginary term of the relative magnetic permeability may begin to increase in the frequency range from 0.5 GHz to less than 1 GHz.
  • the magnetic material for magnetic field amplification of this embodiment may be used in a range of 1 MHz or more and less than 0.5 GHz, and preferably used in a range of 1 MHz or more and less than 0.1 GHz.
  • magnetic materials for magnetic field amplification include wireless power supply coils, magnetic field amplification materials for RFID (Radio Frequency Identification) tags, transformers, inductors, and reactors for high frequency circuits exceeding 20 MHz.
  • RFID Radio Frequency Identification
  • it can be attached as a thin sheet to the back of an antenna or receiver/transmitter, and the magnetic flux can be concentrated within the sheet due to its magnetic field amplification properties, or it can be inserted inside a cylindrical or rectangular parallelepiped coil, or it can be inserted into a donut-shaped or yoke-shaped coil.
  • the real number term of the relative magnetic permeability of the coil is improved by winding a conducting wire around the magnetic core, and the result is used as a magnetic material for magnetic field amplification.
  • the magnetic material for magnetic field amplification of this embodiment is characterized in that the real number term of relative magnetic permeability is high even in a high frequency region.
  • the real number term of relative magnetic permeability at a frequency of 1 MHz to 20 MHz is preferably 3 or more, more preferably 4 or more.
  • the real number term of the relative magnetic permeability at a frequency greater than 20 MHz and less than 1 GHz is preferably 2 or more, and more preferably 3 or more.
  • the magnetic material for magnetic field amplification of the present embodiment can have a real number term ⁇ ' of relative magnetic permeability at a frequency of 20 MHz, for example, of 3.2 or more, preferably 3.5 or more, more preferably 4 or more, and 4 or more. .5 or more is more preferable.
  • the real number term ⁇ ' of relative magnetic permeability at a frequency of 20 MHz can be, for example, 200 or less, and may be 100 or less.
  • tan ⁇ ( ⁇ ''/ ⁇ ') and phase angle ⁇ at 20 MHz are more preferably 0.33 or less and 79° or more, 0.29 or less and 80° or more, and 0.25 More preferably, the tan ⁇ and phase angle ⁇ at 20 MHz are 0.0001 or less and 88 or more. If the tan ⁇ and phase angle ⁇ at 20 MHz are within the above range, especially around this When used at a high frequency (for example, 10 MHz or more and 30 MHz or less), it is preferable because it becomes an efficient and low-cost magnetic material for amplifying magnetic fields.tan ⁇ ( ⁇ ''/ ⁇ ') and phase angle ⁇ are 79 degrees or more.
  • the complex relative permeability tan ⁇ and phase angle ⁇ are determined by measuring the impedance of the toroidal sample using an impedance analyzer, a (vector) network analyzer, and a BH analyzer, and converting the results into complex relative permeability, tan ⁇ , and phase angle ⁇ .
  • the S-parameter method can be used for measurement.
  • the magnetic material for magnetic field amplification of this embodiment also has the characteristic that the frequency dependence of relative magnetic permeability is small.
  • power is supplied at a frequency of 13.56 MHz, so a magnetic material with a small change in the real term ⁇ ' of relative magnetic permeability in the range of 2 MHz to 20 MHz, including that frequency, has excellent efficiency. It can be used preferably.
  • there are many materials whose relative magnetic permeability changes significantly even at frequencies below 5 MHz, and materials whose real number term of relative magnetic permeability is stable in the range from 2 MHz to 20 MHz can be preferably used for applications in this frequency range.
  • Relative permeability at 2 MHz The ratio of the real term of the relative magnetic permeability at 20 MHz to the real term of the relative magnetic permeability at 20 MHz is preferably 0.8 or more, and more preferably 0.9 or more.
  • the ratio of the real terms of the relative magnetic permeability may be 1.1 or less. If the ratio of the real terms of the relative magnetic permeability is 0.8 or more, the decrease in energy efficiency is reduced and the heat generation of devices incorporating magnetic materials is reduced. There is a tendency that the ratio of the real number term of the relative magnetic permeability is 1.1 or less, which tends to make it easier to control input and output to the device.
  • the magnetic material for magnetic field amplification of this embodiment may contain resin.
  • a composite material of a magnetic material and a resin is called a bonded magnetic material, and the resin contained in the bonded magnetic material may be a thermosetting resin or a thermoplastic resin.
  • the thermoplastic resin include polyphenylene sulfide (PPS), polyetheretherketone (PEEK), liquid crystal polymer (LCP), polyamide (PA), polypropylene (PP), polyethylene (PE), thermoplastic elastomer, and the like.
  • Thermosetting resins include epoxy resin, phenol resin, urea resin, melamine resin, guanamine resin, unsaturated polyester resin, vinyl ester resin, diallyl phthalate resin, polyurethane resin, silicone resin, polyimide resin, alkyd resin, furan resin, Examples include dicyclopentadiene resin, acrylic resin, allyl carbonate resin, and thermosetting elastomer commonly called rubber.
  • the content of the resin contained in the bonded magnetic material is preferably 0.1% by mass or more and 95% by mass or less.
  • the content of the resin component is 0.1% by mass or more, the impact resistance is further improved, and when the content is 95% by mass or less, an extreme decrease in relative magnetic permeability and magnetization can be suppressed.
  • the range of 0.5% by mass to 50% by mass is further increased for the same reason as above.
  • it is most preferably in the range of 1% by mass or more and 15% by mass or less.
  • the real number term of relative magnetic permeability is particularly high as the magnetic material for magnetic field amplification of this embodiment, and in order to have particularly good absorption characteristics as an ultra-high frequency absorbing material, it should be 15% by mass or less, although it varies somewhat depending on the application. It is preferable to do so. Molded bodies that do not undergo sintering and hardening and do not contain resin, such as green compacts that use auxiliary agents such as volatile organic solvents, are extremely brittle and cannot be used in the magnetic fields of wireless power supply coils or magnetic cores of inductors that are subject to loads.
  • the resin content is preferably 0.1% by mass or more and 95% by mass or less, more preferably 0.5% by mass or more and 50% by mass or less, and 1% by mass or more and 15% by mass or less. % or less is more preferable.
  • a resin compound for a bonded magnetic material can be obtained, for example, by mixing and/or kneading ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder and a resin at a temperature of 180° C. or higher and 300° C. or lower using a kneader. be able to.
  • ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder and resin are mixed in a mixer, then kneaded in a twin-screw extruder, the extruded strand is cooled in air, and then cut into several mm size with a pelletizer to form pellets.
  • the resin compound for bonded magnetic material of this embodiment can be obtained.
  • the bonded magnetic material of this embodiment can be manufactured by molding the resin compound using an appropriate molding machine. Specifically, for example, a resin compound melted in the barrel of a molding machine is injection molded into a mold to which a magnetic field is applied, and the axes of easy magnetization are aligned (orientation process) to obtain a magnetically oriented bonded magnetic material. Can be done. Further, by calendering or hot press molding a pellet-shaped resin compound, a sheet-shaped bonded magnetic material sheet for magnetic field amplification or a bonded magnetic material sheet for ultra-high frequency absorption can be produced.
  • this By rolling this to a thickness of 20 ⁇ m or more and 200 ⁇ m or less, it can be made into a magnetic material for magnetic field amplification with a high real number term of relative magnetic permeability, and can be suitably used as a molded sheet of magnetic material for magnetic field amplification for RFID tags, for example. It is used as a molded sheet of magnetic material for ultra-high frequency absorption in mobile devices.
  • the ultra-high frequency absorbing magnetic material of this embodiment is characterized by containing ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder.
  • ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder it has an imaginary term with a relative magnetic permeability in which ⁇ ” is higher than 0 in the range of 1 GHz to 0.11 THz, and may have excellent absorption properties, such as having a ⁇ '' of 0.8 or more.
  • the average particle diameter of the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder is preferably 0.1 ⁇ m or more and 10 ⁇ m or less.
  • the reason for this is as mentioned above, but in the ultra-high frequency range of 1 GHz or more, powders with a diameter of 3 ⁇ m or more tend to have a lower relative magnetic permeability due to the skin effect, so the powder particle size should be as much as possible than 0.1 ⁇ m. Furthermore, direct contact between magnetic particles must be avoided as much as possible.
  • rare earth-iron-nitrogen magnetic powder with a diameter of 30 ⁇ m when trying to apply rare earth-iron-nitrogen magnetic powder with a diameter of 30 ⁇ m to a magnetic material for ultra-high frequencies, even if it is crushed to 5 ⁇ m or less, when molded, the magnetic powders come into contact with each other and conduct.
  • the average size of the aggregates may be 30 ⁇ m.
  • the effect of particle size on high frequency characteristics will be the same as in the case of using powder before pulverization, and the purpose of pulverization will be lost.
  • molding methods that apply heat and pressure at the same time, such as hot pressing or calendering are often applied, but in this case, an insulating film such as a phosphorous compound tightly adheres to the surface of the magnetic particles.
  • the magnetic particles are electrically insulated.
  • heat and pressure can be applied simultaneously to create high density and high relative permeability. It can be made into a high frequency magnetic material with magnetic property.
  • the ultra-high frequency absorbing magnetic material of this embodiment has a feature that the imaginary term ⁇ '' of the relative magnetic permeability is high even at ultra-high frequencies.
  • the imaginary term ⁇ '' of the relative magnetic permeability at a frequency of 1 GHz or more and less than 20 GHz is 0. .2 or more is preferable, and 0.3 or more is more preferable.
  • the imaginary term ⁇ '' of the relative magnetic permeability at a frequency of 20 GHz or more and 1 THz or less is preferably 0.01 or more, and more preferably 0.1 or more.
  • the imaginary term ⁇ '' of the relative magnetic permeability can be 0.3 or more, preferably 0.5 or more, more preferably 0.7 or more, and even more preferably 0.9 or more.
  • the imaginary term ⁇ '' of the relative magnetic permeability at a frequency of 10 GHz can be 5 or less, and may be 4 or less.
  • the imaginary term ⁇ '' of relative magnetic permeability at a frequency of 0.11 THz of the magnetic material for use can be set to 0.01 or more, preferably 0.02 or more, more preferably 0.05 or more, and 0.1 or more. More preferred.
  • the imaginary term ⁇ '' of the relative magnetic permeability at a frequency of 0.11 THz can be 2 or less, and may be 1.5 or less.
  • the ratio of the imaginary term ⁇ '' in the relative magnetic permeability at a frequency of 10 GHz to the imaginary term ⁇ '' in the relative magnetic permeability at a frequency of 0.11 THz is preferably 0.01 or more, and 0.01 or more. More preferably, it is 1 or more.
  • the ratio of the imaginary term ⁇ '' of the relative magnetic permeability at 0.11 THz to the imaginary term ⁇ '' of the relative magnetic permeability at a frequency of 10 GHz is 5 or less.
  • the ratio of the imaginary term ⁇ '' in the relative magnetic permeability at 0.11 THz to the imaginary term ⁇ '' in the relative magnetic permeability at a frequency of 10 GHz of the ultra-high frequency absorbing magnetic material is within the above range. , can exhibit higher absorption characteristics in a wide frequency band.
  • the ultra-high frequency absorbing magnetic material of this embodiment contains ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder, and is therefore capable of absorbing ultra-high frequencies in an ultra-wide frequency range from 1 GHz to 1 THz.
  • Magnetic materials with low relative magnetic permeability in a narrow band with a bandwidth of about 10 GHz such as uniaxial magnetocrystalline anisotropic materials such as hexagonal ferrite, borides, and epsilon iron oxide, which are expected to be used at extremely high frequencies. draws the line.
  • uniaxial magnetocrystalline anisotropic materials such as hexagonal ferrite, borides, and epsilon iron oxide
  • a major feature is that it is contained.
  • Magnetic materials for ultra-high frequency absorption include 5G (5th Generation Mobile Communication System), 5G+ (5th Generation Plus Mobile Communication System), and 5G+ (5th Generation Plus Mobile Communication System).
  • ile Communication System) and 6G (6th Generation Mobile Communication System) Ultra-high frequency signals and spurious signals applied to infrastructure equipment such as mobile communication devices, small mobile phone base stations and cloud base stations, their equipment, devices, antennas, etc.
  • Absorption members Intelligent Transport Systems
  • Wireless HDMI registered trademark
  • Wireless High-Definition Multimedia Interface Wireless LAN (Wireless Local Area Network: LoC) al Area Network
  • materials for absorbing ultra-high frequency signals and spurious signals for equipment and devices used in satellite broadcasting (Ka-band), etc. and electromagnetic noise absorbing materials for personal computers that mainly remove the 2nd to 7th harmonics. .
  • the ultra-high frequency absorbing magnetic material of this embodiment may contain resin.
  • a composite material of a magnetic material and a resin is called a bonded magnetic material, and the resin contained in the bonded magnetic material may be a thermosetting resin or a thermoplastic resin.
  • the thermoplastic resin include polyphenylene sulfide (PPS), polyetheretherketone (PEEK), liquid crystal polymer (LCP), polyamide (PA), polypropylene (PP), polyethylene (PE), thermoplastic elastomer, and the like.
  • Thermosetting resins include epoxy resin, phenol resin, urea resin, melamine resin, guanamine resin, unsaturated polyester resin, vinyl ester resin, diallyl phthalate resin, polyurethane resin, silicone resin, polyimide resin, alkyd resin, furan resin, Examples include dicyclopentadiene resin, acrylic resin, allyl carbonate resin, and thermosetting elastomer commonly called rubber.
  • the content of the resin contained in the bonded magnetic material is preferably 0.1% by mass or more and 95% by mass or less.
  • the content of the resin component is 0.1% by mass or more, the impact resistance is further improved, and when the content is 95% by mass or less, an extreme decrease in relative magnetic permeability and magnetization can be suppressed.
  • the range of 0.5% by mass or more and 50% by mass or less is more suitable for the same reason as above.
  • the content is more preferably in the range of 1% by mass or more and 15% by mass or less.
  • the real number term of relative magnetic permeability is particularly high as the magnetic material for magnetic field amplification of this embodiment, and in order to have particularly good absorption characteristics as an ultra-high frequency absorbing material, it should be 15% by mass or less, although it varies somewhat depending on the application. It is preferable to do so. Molded bodies that do not undergo sintering and hardening and do not contain resin, such as green compacts that use auxiliary agents such as volatile organic solvents, are extremely brittle and cannot be used in the magnetic fields of wireless power supply coils or magnetic cores of inductors that are subject to loads.
  • the resin content is preferably 0.1% by mass or more and 95% by mass or less, more preferably 0.5% by mass or more and 50% by mass or less, and 1% by mass or more and 15% by mass or less. % or less is more preferable.
  • a resin compound for a bonded magnetic material can be prepared by mixing and/or kneading a phosphorus compound, an ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder, and a resin at a temperature of 180°C or higher and 300°C or lower using a kneader, for example. Alternatively, it can be obtained by mixing and/or kneading ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder and a resin.
  • ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder and resin are mixed in a mixer, then kneaded in a twin-screw extruder, the extruded strand is cooled in air, and then cut into several mm size with a pelletizer to form pellets.
  • the resin compound for bonded magnetic material of this embodiment can be obtained.
  • the bonded magnetic material of this embodiment can be manufactured by molding the resin compound using an appropriate molding machine. Specifically, for example, a resin compound melted in the barrel of a molding machine is injection molded into a mold to which a magnetic field is applied, and the axes of easy magnetization are aligned (orientation process) to obtain a magnetically oriented bonded magnetic material. Can be done. Further, by calendering or hot press molding a pellet-shaped resin compound, a sheet-shaped bonded magnetic material sheet for magnetic field amplification or a bonded magnetic material sheet for ultra-high frequency absorption can be produced.
  • this By rolling this to a thickness of 20 ⁇ m or more and 200 ⁇ m or less, it can be made into a magnetic material for magnetic field amplification with a high real number term of relative magnetic permeability, and can be suitably used as a molded sheet of magnetic material for magnetic field amplification for RFID tags, for example. It is used as a molded sheet of magnetic material for ultra-high frequency absorption in mobile devices.
  • the method for producing ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder of the present embodiment includes rare earth R (R is Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Rare earth-iron-nitrogen magnetic powder containing at least one member selected from the group consisting of Sm (if Sm is included, Sm is less than 50 atomic % with respect to the entire R component), Fe, and N.
  • a phosphorus compound coating is formed on the rare earth-iron-nitrogen magnetic powder, and a rare earth-containing phosphorus compound-coated portion is formed on the rare earth-iron-nitrogen magnetic powder.
  • [Phosphorus treatment process] In the phosphorus treatment step, an inorganic acid is added to a slurry containing a rare earth-iron-nitrogen magnetic powder containing R, Fe, and N, water, and a phosphorus-containing material to form a rare-earth-iron material having a phosphorus compound coating.
  • a rare earth-iron-nitrogen magnetic powder having a phosphorus compound coating is composed of metal components (e.g., iron, neodymium, etc.) contained in the rare-earth-iron-nitrogen magnetic powder and phosphorus components (e.g., phosphorus) contained in the phosphorus-containing material.
  • the rare earth-iron-nitrogen magnetic powder having a phosphorus compound-coated portion is formed by precipitating a phosphorus compound on the surface of the rare-earth-iron-nitrogen magnetic powder. It is preferable to form this by coating the surface of the part (such a coating is referred to as a "phosphorus compound coating"; a part formed by such coating is referred to as a "phosphorus compound coated part").
  • a phosphorus compound-coated rare earth-iron-nitrogen magnetic powder having a thick coating portion (also referred to as film thickness) can be obtained, improving tan ⁇ and phase angle ⁇ , and improving magnetic field amplification characteristics.
  • phosphorus compounds such as phosphates with smaller particle sizes are precipitated compared to the case where an organic solvent is used.
  • a rare earth-iron-nitrogen magnetic powder having the following characteristics is obtained, and tends to have excellent efficiency in a high frequency region and excellent absorption characteristics in an ultra-high frequency region.
  • a method for producing a slurry containing rare earth-iron-nitrogen magnetic powder containing R, Fe, and N, water, and a phosphorus-containing substance is not particularly limited, but for example, rare earth-iron-nitrogen magnetic powder, It is obtained by mixing a phosphorus-containing substance solution containing a phosphorus-containing substance using water as a solvent.
  • the content of the rare earth-iron-nitrogen magnetic powder in the slurry is preferably 1% by mass or more and 50% by mass or less, and more preferably 5% by mass or more and 20% by mass or less from the viewpoint of productivity.
  • the content of the phosphorus-containing substance in the slurry is not particularly limited, but when the phosphorus-containing substance is phosphoric acid and is composed only of hydrogen and phosphoric acid components (PO 4 ), the content is expressed as PO 4 equivalent amount. , for example, from 0.01% by mass to 10% by mass, and preferably from 0.05% by mass to 5% by mass from the viewpoint of reactivity between the metal component and the phosphoric acid component and productivity.
  • Examples of phosphorus-containing substances include phosphorus alone and its compositions, phosphoric acid compounds such as orthophosphoric acid, heteropolyacid compounds such as phosphotungstic acid and phosphomolybdic acid, phosphorus-containing acid compounds such as phosphoric acid compounds and heteropolyacid compounds, and metal ions. Or salts with ammonium ions, organic phosphorus compounds such as phosphate esters, phosphite esters, phosphine oxides, iron phosphide, phosphor bronze, Fe-BP-Cu and Fe-Nb-BP alloys, etc. Examples include phosphorus-containing metals.
  • a phosphoric acid aqueous solution can be obtained by mixing the phosphoric acid compound and water.
  • phosphoric acid compounds include orthophosphoric acid, sodium dihydrogen phosphate, sodium monohydrogen phosphate, ammonium dihydrogen phosphate, ammonium monohydrogen phosphate, zinc phosphate, calcium phosphate, and hypophosphorous.
  • examples include inorganic phosphoric acids such as acid-based, hypophosphite-based, pyrophosphoric acid-based, and polyphosphoric acid-based acids, and organic phosphoric acids. These may be used alone or in combination of two or more.
  • oxoacid salts such as molybdate, tungstate, vanadate, and chromate, sodium nitrate, and sodium nitrite.
  • Oxidizing agents such as EDTA, chelating agents such as EDTA, etc. can be used as additives.
  • inorganic phosphoric acids such as orthophosphoric acid, pyrophosphoric acid, and polyphosphoric acid, as well as Na, Ca, Pb, Zn, Fe, Y, and Ce, are recommended from the viewpoint of reaction control and coating amount control.
  • Preferred are phosphoric acid compounds such as phosphates with , Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, Sm, ammonium, etc.
  • the concentration of phosphoric acid in the phosphoric acid aqueous solution is preferably 5% by mass or more and 50% by mass or less, and 10% by mass or more from the viewpoint of solubility of the phosphoric acid compound, storage stability, and ease of chemical conversion treatment. More preferably, it is 30% by mass or less.
  • the pH of the phosphoric acid aqueous solution is preferably 1 or more and 4.5 or less, and more preferably 1.5 or more and 4 or less from the viewpoint of easy control of the precipitation rate of phosphate.
  • the pH can be adjusted using dilute hydrochloric acid, dilute sulfuric acid, etc.
  • the slurry is made acidic by adding an inorganic acid, and the pH is preferably adjusted to 1 or more and 4.5 or less, more preferably 1.6 or more and 3.9 or less. , more preferably adjusted to 2 or more and 3 or less.
  • the pH is less than 1
  • the rare earth-iron-nitrogen magnetic powders aggregate starting from locally precipitated phosphorus compounds in large quantities, resulting in worsening of tan ⁇ and phase angle ⁇ in the high frequency range, and in the ultra-high frequency range. ⁇ " tends to decrease.
  • the inorganic acid to be added include hydrochloric acid, nitric acid, sulfuric acid, boric acid, and hydrofluoric acid.
  • inorganic acids are used from the viewpoint of waste liquid treatment, organic acids can be used in combination depending on the purpose. Examples of organic acids include acetic acid, formic acid, and tartaric acid.
  • the phosphorus treatment step can also be carried out so that the phosphorus content in the obtained magnetic powder is 0.02% by mass or more.
  • the phosphorus content in the magnetic powder obtained in the phosphorus treatment step is preferably 0.05% by mass or more, more preferably 0.15% by mass or more.
  • the phosphorus content in the magnetic powder obtained in the phosphorus treatment step is preferably 4% by mass or less, more preferably 2% by mass or less, and even more preferably 1% by mass or less.
  • the phosphorus content is preferably 0.15% by mass or more and 1% by mass or less.
  • the bulk phosphorus content of the entire magnetic powder is: It can be measured using ICP-AES (ICP emission spectroscopy).
  • the local phosphorus content in the magnetic powder phase and phosphorus compound-coated parts of phosphorus compound-coated powder can be measured using STEM-EDX line analysis.
  • the phosphorus (P) atom concentration in the phosphorus compound coated part is preferably 1 at% or more, more preferably 5 at% or more.
  • the P atom concentration in the phosphorus compound coated part is , may be 25 atom % or less, preferably 15 atom % or less. If the phosphorus content in the phosphorus compound coating is less than 1 atom %, the electrical insulation properties of the phosphorus compound tend to be difficult to function. If it exceeds 25 at %, not only the real term of relative magnetic permeability in the high frequency region and the imaginary term of the relative magnetic permeability in the ultrahigh frequency region tend to decrease, but also the corrosion resistance performance tends to decrease.
  • the rare earth (R) atom concentration in the phosphorus compound coating portion existing on the surface of the obtained magnetic powder is the same as the R atom concentration in the rare earth (R)-iron-nitrogen magnetic powder that is the base material. It may also be done to have a higher region (R high concentration region).
  • the R atom concentration in the R high concentration region can be 1.05 times or more the R atom concentration in the core region in the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder, and 1.1 times or more. It is preferably 1.2 times or more, more preferably 1.5 times or more.
  • the R atom concentration in the R high concentration region can be, for example, four times or less than the R atom concentration in the core region of the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder.
  • the R high concentration region is a region including a layer exhibiting a P (phosphorus) peak in STEM-EDX line analysis of ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder.
  • the thickness of the R high concentration region can be, for example, 1 nm or more, preferably 3 nm or more and 150 nm or less, more preferably 10 nm or more and 100 nm or less, and even more preferably 20 nm or more and 80 nm or less.
  • the atomic concentration (atomic %) of each element in the R high concentration region is determined by averaging the atomic concentration in the phosphorus compound coating part in STEM-EDX line analysis.
  • the rare earth element (R) may be, for example, Nd, and in that case, the Nd atomic concentration can be evaluated as a high Nd concentration region.
  • Adjustment of the pH of the slurry containing rare earth-iron-nitrogen magnetic powder, water, and phosphorus-containing material to a range of 1 to 4.5 is preferably carried out for 10 minutes or more, and the thickness of the coating is thin. From the viewpoint of reducing the portion size, it is more preferable to carry out the process for 30 minutes or more.
  • the pH rises quickly, so the interval of adding inorganic acid for pH control is short, but as the coating progresses, the pH fluctuation gradually becomes gentler, and the interval of adding inorganic acid becomes longer, so that the end point of the reaction can be reached. I can judge.
  • the rare earth-iron-nitrogen magnetic powder having the phosphorus compound coating obtained in the phosphorus treatment step is oxidized by heat treatment at 350° C. or higher and 600° C. or lower in an oxygen-containing atmosphere. Through the oxidation treatment, the surface of the rare earth-iron-nitrogen magnetic powder is oxidized from the interface between the phosphorus compound coating and the rare earth-iron-nitrogen magnetic powder, forming a nano ⁇ -Fe separated phase and an R oxynitride phase. It is believed that a disproportionate ⁇ -Fe-containing region is formed.
  • This iron oxide phase may be any one or more of hematite, magnetite, ferrite, and wustite, but this iron oxide phase is often hematite. Further, the iron oxide phase may be bonded or free on the surface of the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder.
  • iron oxide phase In applications where better efficiency is required, it is preferable to keep this iron oxide phase bound, whereas in applications where higher ⁇ ' is required, it is better to leave it free.
  • means for liberating the iron oxide phase include mechanically knocking it off by tumbling or the like, and dissolving only the iron oxide phase by reaction with an acid.
  • the oxidation treatment is performed by heat-treating the magnetic powder after the phosphorus treatment in an oxygen-containing atmosphere.
  • the reaction atmosphere preferably contains oxygen in an inert gas such as nitrogen or argon.
  • the oxygen concentration is preferably 3 vol% or more and 21 vol% or less, more preferably 3.5 vol% or more and 10 vol% or less.
  • the temperature during the oxidation treatment is 350°C or more and 600°C or less, preferably 380°C or more and 550°C or less, more preferably 400°C or more and 500°C or less, and even more preferably 420°C or more and 480°C or less. If the temperature is lower than 350° C., the formation of the ⁇ -Fe-containing region is insufficient, and the real number term of the relative magnetic permeability in the high frequency region tends to decrease. If the temperature exceeds 600°C, the magnetic powder tends to decompose excessively.
  • the reaction time is preferably 3 hours or more and 10 hours or less.
  • the thermal decomposition temperature of the rare earth-iron-nitrogen magnetic powder in the core region is about 550 to 650°C. It is also known that in an oxygen-containing atmosphere, oxidative deterioration occurs at temperatures above 200°C. Among these, it has not been previously known that the material can be heated to a temperature close to the thermal decomposition temperature in an oxygen-containing atmosphere and then used as an excellent ⁇ -Fe-containing rare earth-iron-nitrogen magnetic material. After a dense film is produced on rare earth-iron-nitrogen magnetic powder by the phosphorus treatment of the present disclosure, heat treatment is performed in an oxygen-containing atmosphere to prevent excessive thermal decomposition of the core region, and to prevent the core region from being thermally decomposed excessively.
  • the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic material of the present invention is produced by gradually separating and dispersing ⁇ -Fe from the matrix at the nano-level through a disproportionation reaction from the surface of the rare earth-iron-nitrogen magnetic powder. It is thought that it is possible to create It had never been imagined that a magnetic material produced through such an unprecedented process would have excellent efficiency and high ⁇ '.
  • the mechanism by which the ⁇ -Fe-containing region is formed is thought to be, for example, as follows. Oxygen is gradually supplied through the phosphorus compound coating on the surface of the rare earth-iron-nitrogen powder and the interface between it and the rare-earth-iron-nitrogen powder, and the rare earth-iron-nitrogen material and oxygen are supplied from the surface and/or interface. As the reaction (oxidation process) progresses slowly, the rare earth-iron-nitrogen material transforms into a disproportionate layer of ⁇ -Fe phase and R oxynitride phase, resulting in a unique nano-level phase separation. An " ⁇ -Fe-containing region" is generated.
  • the rare-earth-iron-nitrogen magnetic powder will simply be oxidized and nitrogen will dissipate into the atmosphere. Therefore, the reaction occurs more rapidly than in the case of the present invention. As a result, it changes into a mixture of (1) ⁇ -Fe or iron oxide and (2) rare earth oxide.
  • (1) and (2) have no lattice matching, so unlike the ⁇ -Fe-containing region of the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic material of the present invention, the regular arrangement of ⁇ -Fe, It tends to become a non-uniform phase with no orientation.
  • the magnetic powder that has undergone the phosphorus treatment step and the oxidation step may be treated with silica if necessary. Oxidation resistance can be improved by forming a silica thin film on magnetic powder.
  • a silica thin film can be formed, for example, by mixing an alkyl silicate, magnetic powder, and an alkaline solution.
  • the magnetic powder treated with silica may be further treated with a silane coupling agent.
  • a silane coupling agent film is formed on the silica thin film, improving the magnetic properties of the magnetic powder, improving wettability with resin, and molding.
  • the silane coupling agent is not particularly limited as long as it can be selected according to the type of resin, but examples include ⁇ -(2-aminoethyl)aminopropyltrimethoxysilane, ⁇ -(2-aminoethyl)aminopropylmethyldimethoxysilane , ⁇ -methacryloxypropyltrimethoxysilane, ⁇ -methacryloxypropylmethyldimethoxysilane, N- ⁇ -(N-vinylbenzylaminoethyl)- ⁇ -aminopropyltrimethoxysilane hydrochloride, ⁇ -glycidoxypropyltri Methoxysilane, ⁇ -mercaptopropyltrimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, vinyltriacetoxysilane, ⁇ -chloropropyltrimethoxysilane, hexamethylenedisil
  • Examples include silane coupling agents. These silane coupling agents may be used alone or in combination of two or more.
  • the amount of the silane coupling agent added is preferably 0.2 parts by mass or more and 0.8 parts by mass or less, more preferably 0.25 parts by mass or more and 0.6 parts by mass or less, per 100 parts by mass of the magnetic powder. If it is less than 0.2 parts by mass, the effect of the silane coupling agent is small, and if it exceeds 0.8 parts by mass, the magnetic powder tends to agglomerate, resulting in a decrease in the magnetic properties of the magnetic powder or molded body.
  • isopropyltriisostearoyl titanate isopropyltri(N-aminoethyl-aminoethyl)titanate, isopropyltris(dioctyl) without performing the silica treatment step and/or the silane coupling treatment step, or after these treatment steps.
  • pyrophosphate) titanate tetraisopropyl bis(dioctyl phosphite) titanate, tetraisopropyl titanate, tetrabutyl titanate, tetraoctyl bis(ditridecyl phosphite) titanate, isopropyltrioctanoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl tri( Dioctyl phosphate) titanate, bis(dioctyl pyrophosphate) ethylene titanate, isopropyl dimethacrylylisostearoyl titanate, tetra(2,2-diallyloxymethyl-1-butyl) bis(ditridecyl phosphite) titanate, isopropyl tricumylphenyl titanate, etc.
  • the surface of magnetic powder can be treated using titanium-based coupling agents, aluminum-based coupling agents such as acetalkoxyaluminum diisopropylate, zirconium-based, chromium-based, iron-based, tin-based coupling agents, etc. .
  • titanium-based coupling agents aluminum-based coupling agents such as acetalkoxyaluminum diisopropylate, zirconium-based, chromium-based, iron-based, tin-based coupling agents, etc.
  • the affinity with the added resin improves, and the isolated dispersion of the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder becomes more pronounced, making the powder more compact.
  • electrical insulation is created between the two, resulting in excellent efficiency in the high frequency range and excellent absorption characteristics in the ultra-high frequency range.
  • the magnetic powder can be filtered, dehydrated, and dried by a conventional method.
  • the rare earth-iron-nitrogen magnetic powder can improve the real number term of relative magnetic permeability by making the particle size distribution uniform.
  • the particle size distribution can be made uniform by a general dry classification method or a wet classification method.
  • the particle size distribution may be made uniform at any point before the phosphoric acid treatment, after the phosphorus treatment step, after the oxidation step, after the silica treatment step, or after the silane coupling treatment step.
  • the rare earth-iron-nitrogen magnetic powder used in the manufacturing method of this embodiment is R (where R is Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, Sm). At least one selected from the above, and when Sm is included, Sm is less than 50 atomic % of the entire R component), Fe, and N. R is at least one selected from Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Sm; is preferable from the viewpoint of stability of raw material supply and realization of high relative magnetic permeability, and Nd, Y, Ce, and Pr are more preferable from the viewpoint of cost.
  • the content of Sm with respect to the entire R component is less than 50 atom %, and more preferably less than 20 atom %.
  • the content of Nd or Pr is 50 atomic % or more of the entire R component, a magnetic material having higher relative magnetic permeability and improved tan ⁇ and phase angle ⁇ can be obtained.
  • the Nd or Pr content is 70 atomic percent or more, and the absolute value of the magnetocrystalline anisotropy field (the magnitude of the magnetic anisotropy) is A rare earth-iron-nitrogen magnetic powder made of NdFeN with a Nd content of 100 atomic % is particularly preferable because it has a large index (indicating .
  • the content of Fe in the rare earth-iron-nitrogen magnetic powder is preferably 40 atomic % or more and 87 atomic % or less, more preferably 50 atomic % or more and 85 atomic % or less.
  • the evaluation method performed in the example is as follows. (1) Elemental Content The concentrations of P and Mo in the magnetic powder were measured using ICP emission spectrometry (ICP-AES SPS3500 manufactured by Hitachi High-Tech Science). The concentrations of O and N in the magnetic powder were measured using an oxygen/nitrogen analyzer (EMGA-820 manufactured by Horiba, Ltd.).
  • the ratio (I)/(II) of the diffraction peak intensity (I) of the (110) plane of ⁇ -Fe to the peak intensity (II) of the strongest line of the rare earth-iron-nitrogen compound in the core region was calculated.
  • Average particle size The average particle size of the magnetic powder was measured using a laser diffraction particle size distribution device (MALVERN Inst. MASTERSIZER 2000).
  • a resin compound was prepared by mixing the magnetic powder and an epoxy resin, which is a thermosetting resin, so that the content of the magnetic powder was 97% by mass, and then kneading the mixture.
  • This resin compound was charged into a mold with an inner diameter of 3.1 mm and an outer diameter of 8 mm, and was molded with a pressure of 0.8 GPa, followed by heat curing in a vacuum at 150° C. for 2 hours to produce a toroidal molded body.
  • the complex relative magnetic permeability in the frequency range of 1 MHz to 1 GHz was evaluated using an impedance analyzer (HP4291B, manufactured by Hewlett-Packard) based on the inductance value obtained from a single-turn inductor type test fixture.
  • STEM-EDX analysis and TEM-ED analysis STEM analysis of the surface of the magnetic powder was performed as follows. First, the obtained magnetic powder was coated with carbon and then cross-sectioned and processed into thin pieces using a focused ion beam (FIB). The obtained sample was analyzed using a STEM (manufactured by FEI, model number Talos F200X; acceleration voltage 200 kV) and a STEM-EDX attached to the STEM (system: manufactured by FEI, model number SuperX, detector: SDD detector manufactured by Bruker). It was measured using Line analysis was performed from the outside to the inside of the magnetic powder with the step width described below, and continuous changes in the atomic concentration of each constituent element were observed.
  • FIB focused ion beam
  • the atomic concentration was calculated as the sum of the elements excluding C. . Further, the crystallinity and orientation of the ⁇ -Fe-containing region of the magnetic powder were evaluated using TEM-ED.
  • Nd 2 Fe 17 N 3 magnetic powder having an average particle size of about 15 ⁇ m and not subjected to phosphorus treatment was produced as follows.
  • Nd-Fe sulfuric acid solution 5.0 kg of FeSO 4 .7H 2 O was mixed and dissolved in 2.0 kg of pure water. Further, 0.45 kg of Nd 2 O 3 and 0.70 kg of 70% sulfuric acid were added and stirred well to completely dissolve them. Next, pure water was added to the obtained solution to adjust the final Fe concentration to 0.726 mol/L and Nd concentration to 0.106 mol/L, thereby preparing a Nd-Fe sulfuric acid solution.
  • Pre-treatment process 100 g of Nd--Fe oxide was placed in a steel container so as to have a bulk thickness of 10 mm. After the container was placed in a furnace and the pressure was reduced to 100 Pa, the temperature was raised to the pretreatment temperature of 850° C. while introducing hydrogen gas, and the temperature was maintained for 15 hours to obtain a black powder partial oxide.
  • the Nd 2 Fe 17 N 3 magnetic powder produced in Production Example 1 was subjected to phosphorus treatment as follows.
  • a phosphoric acid treatment solution mix 85% orthophosphoric acid: sodium dihydrogen phosphate: sodium molybdate dihydrate at a mass ratio of 1:6:1, adjust the pH to 2 with pure water and dilute hydrochloric acid, and adjust the PO 4 concentration.
  • a sample adjusted to 20% by mass was prepared.
  • the Nd-Fe-N magnetic powder obtained in the water washing process was stirred for 1 minute in dilute hydrochloric acid containing 1000 g of water and 70 g of hydrogen chloride to remove the surface oxide film and dirt components, and the conductivity of the supernatant liquid was 100 ⁇ S.
  • Drainage and water injection were repeated until the concentration of the powder was reduced to less than /cm to obtain a slurry containing 10% by mass of Nd--Fe--N anisotropic magnetic powder.
  • the entire amount of 100 g of the prepared phosphoric acid treatment solution was added into the treatment tank, and then 6% by mass of hydrochloric acid was added at any time to adjust the pH of the phosphoric acid treatment reaction slurry to 2.0 ⁇ 0.
  • the temperature was controlled within a range of .1 and maintained for 40 minutes.
  • the powder was suction-filtered, dehydrated, and vacuum-dried to obtain an anisotropic Nd--Fe--N magnetic powder having a phosphorus compound coating.
  • Comparative Examples 2 to 3 300 g of the Nd-Fe-N anisotropic magnetic powder having a phosphorus compound coating of Comparative Example 1 was heated gradually from room temperature in an atmosphere of a mixed gas of nitrogen and air (oxygen concentration 4% by volume, 5 L/min). Then, heat treatment was carried out for 8 hours at the maximum temperature listed in Table 1 to obtain oxidized rare earth-iron-nitrogen magnetic powders (average particle size of about 15 ⁇ m) of Examples 1 and 2.
  • the content of oxygen O in the magnetic powder hardly changes at processing temperatures up to 320°C. This indicates that the presence of the phosphorus compound coating suppresses oxidation of the magnetic powder. Further, at a treatment temperature of 350° C. or higher, O gradually increases and at the same time, the broad peak intensity of ⁇ -Fe begins to increase. This indicates that at a processing temperature of 350° C. or higher, the R oxynitride phase and nano-sized ⁇ -Fe begin to be generated, and an ⁇ -Fe-containing region begins to be formed. Further, it is considered that the diffraction peak of hematite starts to grow from 380° C., and an iron oxide layer is formed on the outside of the phosphorus compound coating.
  • Example 2 Comparative Example 1 (FIGS. 2A and 2B), Example 1 (FIGS. 3A and 3B), Example 2 (FIGS. 4A and 4B, FIGS. 5A and 5B), and Example 4 (FIGS. 6A and 6B, FIGS. 7A and 7B) , Fig. 8), STEM, EDX, TEM, and ED images near the surface of the magnetic powder were observed.
  • Example 2 only STEM (manufactured by JEOL Ltd., model number JEM-F200; acceleration voltage 200 kV) and STEM-EDX attached to STEM (system: manufactured by JEOL Ltd., model number SD100HR, detector: dry SD detector manufactured by JEOL Ltd.) ) was observed.
  • FIG. 10 shows an enlarged view of the ⁇ -Fe-containing region in FIG. 3A.
  • Table 2 shows the atomic concentrations of N, O, Fe, and Nd in Area 1 and Area 2 in FIG. 10.
  • Nd contains more oxygen than Fe
  • Area 1 which is an "island” region, exists in the form of R oxide phase (or R oxynitride phase).
  • Area 2 which is a "sea" region that contains a large amount of Fe, exists. From FIG. 3B (Example 1), FIG. 4B (Example 2), and FIG. 6B (Example 4), it is thought that Examples 1, 2, and 4 contain a phosphorus compound or an iron oxide layer as a coating. It will be done.
  • nano-sized Fe is ⁇ -Fe
  • the phase containing Nd contains O and N (R oxynitride phase). Guessed.
  • the nano-sized ⁇ -Fe and R oxynitride phases were larger in Example 4.
  • the film thickness of the region containing ⁇ -Fe was approximately 20 nm (Example 1), approximately 400 nm (Example 2), and approximately 4 ⁇ m (Example 4).
  • the line analysis results near the surface and the entire ⁇ -Fe-containing region in Examples 2 and 4 Fig. 4B, Fig. 5B, Fig. 6B, Fig.
  • FIG. 8 shows a STEM image and an electron diffraction image of the ⁇ -Fe-containing region of Example 4.
  • the right figure in FIG. 8 is an electron beam diffraction image of ⁇ -Fe within the 200 nm diameter circle region shown in the left figure in FIG. 8 due to [111] incidence.
  • the inner hexagonal diffraction point with high brightness in the right diagram of FIG. 8 is assigned to ⁇ 110 ⁇ of ⁇ -Fe. It is estimated from EDX image analysis (see Figure 6A) that the size of the ⁇ -Fe phase in this part is 10 nm or less and is uniformly arranged, and a clear spot is observed in the left diagram of Figure 8.
  • the ⁇ -Fe phase is aligned and oriented in one direction within a diameter range of 200 nm.
  • other satellites with low brightness are observed at equal intervals between the origin and the ⁇ 110 ⁇ and ⁇ 220 ⁇ diffraction points derived from ⁇ -Fe.
  • This is considered to be a diffraction point derived from the R oxynitride phase that surrounds the ⁇ -Fe phase and is lattice matched to ⁇ -Fe.
  • both the matrix phase of the material is crystallized, aligned, and oriented. It is thought that the formation of such an orderly structure results in a magnetic powder that achieves both electrical insulation and magnetic connection to a high degree.
  • the respective crystallite diameters were calculated from the peak of the (110) plane of ⁇ -Fe in the XRD pattern of FIG. ), 8.9 nm (Example 3), 8.6 nm (Example 4)). Although the grain size was calculated to be larger than that observed by STEM-EDX, it is possible that the grain size appeared in the diffraction peak as a crystal containing not only the ⁇ -Fe phase but also a portion of the lattice-matched rare earth oxide.
  • ⁇ 1 / ⁇ 2 was less than 0.7, but in Examples 1 to 4, ⁇ 1 / ⁇ 2 was 0.8 or more. This is considered to be because an ⁇ -Fe-containing region is generated by the oxidation step after the phosphorus treatment, and the electrical insulation is improved. Further, in Examples 2 and 3, ⁇ ' was improved even though the density was lower than that in Comparative Examples 1 to 3. This is considered to be because ⁇ -Fe-containing regions are generated by the oxidation step after the phosphorus treatment, increasing the effect of magnetic coupling.
  • ⁇ at 13 MHz is 85° or more (tan ⁇ is 0.0875 or less), and the loss is low and can be suitably used as an RFID antenna material, but in Comparative Examples 1 to 3, , when ⁇ was less than 85° (tan ⁇ exceeded 0.0875), the loss was high and the efficiency was low.
  • Example 5 and comparative example 4 By classifying the magnetic powder obtained in the same manner as in Comparative Example 1, a phosphorus-treated rare earth-iron-nitrogen magnetic powder having an average particle size of about 4 ⁇ m was produced (Comparative Example 4). Further, by classifying the magnetic powder obtained in the same manner as in Example 1, ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder with an average particle size of about 4 ⁇ m was produced (Example 5). The average particle diameters of Comparative Example 4 and Example 5 were measured using a laser diffraction particle size distribution analyzer (HELOS&RODOS, manufactured by Nippon Laser Co., Ltd.).
  • HELOS&RODOS laser diffraction particle size distribution analyzer
  • Resin sheets each having a density of approximately 5.0 g/cm 3 were prepared, and the values of ⁇ '' at 1 GHz, 7.6 GHz (the frequency at which ⁇ '' in Example 5 takes the maximum value), and 10 GHz were evaluated, and the results were evaluated. It is shown in Table 4. In the region of 1 to 10 GHz, the magnetic material of Example 5 showed a higher ⁇ '' than Comparative Example 4.
  • Example 6 By classifying the magnetic powder obtained in the same manner as in Example 2, ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder with an average particle size of about 17 ⁇ m was produced.
  • a laser diffraction particle size distribution analyzer (HELOS&RODOS, manufactured by Nippon Laser Co., Ltd.) was used to measure the average particle size.
  • a toroidal molded body (density 5.58) was prepared by mixing with resin in the same manner as in Examples 1 to 4, and using an impedance analyzer, the complex relative magnetic permeability in the frequency range of 1 MHz to 1 GHz was measured using a one-turn inductor. Evaluation was made from the inductance value obtained from a shaped test fixture. The results are shown in Table 5.
  • Example 2 shows the results of measuring the frequency dependence of complex relative magnetic permeability from 1 MHz to 100 MHz using the method described above.
  • the invention according to the present disclosure may include, for example, the following aspects.
  • Rare earth R R is at least one selected from the group consisting of Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Sm, and includes Sm (Sm is less than 50 atomic % based on the entire R component), a core region containing Fe, and N, and outside the core region, ⁇ -Fe, and an oxide, nitride, and ⁇ -Fe-containing rare earth-iron-nitrogen-based magnetic powder having an ⁇ -Fe-containing region containing at least one member selected from the group consisting of oxynitrides.
  • the ⁇ -Fe-containing region includes nanocrystals made of at least one selected from the group consisting of oxides, nitrides, and oxynitrides of the rare earth R, and nanocrystals made of ⁇ -Fe.
  • ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder according to [1].
  • the thickness of the ⁇ -Fe-containing region is 0.01% or more and less than 50% of the average particle size of the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder, [1] or [2] ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder described in .
  • the core region contains a rare earth-iron-nitrogen compound, and in the XRD diffraction pattern, the diffraction peak intensity (I) of the (110) plane of ⁇ -Fe and the strongest line of the rare earth-iron-nitrogen compound
  • the ⁇ -Fe-containing rare earth-iron-nitrogen magnetism according to any one of [1] to [4], wherein the ratio (I)/(II) to the peak intensity (II) of is 0.01 or more and less than 10. powder.
  • a magnetic material for magnetic field amplification comprising the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder according to any one of [1] to [8].
  • a magnetic material for ultra-high frequency absorption comprising the ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder according to any one of [1] to [8].
  • Rare earth R is at least one selected from the group consisting of Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Sm, and includes Sm has a sea-island structure including a core region containing Fe and N, and a sea region and an island region outside the core region; The atomic concentration (%) of is higher in the island region than in the sea region, and the atomic concentration (%) of rare earths R and O is lower in the island region than in the sea region.
  • -Fe-containing rare earth-iron-nitrogen magnetic powder is at least one selected from the group consisting of Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Sm, and includes Sm has a sea-island structure including a core region containing Fe and N, and a sea region and an island region outside the core region; The atomic concentration (%) of is higher in the island region than in the sea region, and the atomic concentration (%) of rare earth
  • Rare earth R is at least one selected from the group consisting of Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Sm, and includes Sm
  • An inorganic acid is added to a slurry containing a rare earth-iron-nitrogen magnetic powder containing Sm (based on the entire R component), Fe, and N, water, and a phosphorus-containing material.
  • ⁇ -Fe-containing rare earth-iron-nitrogen magnetic powder having excellent magnetic field amplification characteristics and ultra-high frequency absorption characteristics can be obtained.
  • This magnetic powder can be suitably used as a magnetic material for magnetic field amplification and a magnetic material for ultrahigh frequency absorption.
  • These magnetic materials for magnetic field amplification and ultra-high frequency absorption magnetic materials are mainly used in power equipment and information communication related equipment, such as transformers, heads, inductors, reactors, cores (magnetic cores) used in high frequency or ultra-high frequency regions, Materials used in yokes, elements and antennas that transmit and receive high frequencies and ultra-high frequencies such as RFID tags and wireless power supply, microwave elements, magnetostrictive elements, magnetoacoustic elements and magnetic recording elements, Hall elements, magnetic sensors, current sensors, rotation Magnetic materials used in sensors, electronic compasses, and other sensors that use a magnetic field; magnetic materials that suppress interference caused by unnecessary electromagnetic interference, such as electromagnetic noise absorbing materials, electromagnetic wave absorbing materials, and magnetic shielding materials; and noise-eliminating inductors. It can be used for magnetic materials that remove noise from signals in high frequency or ultra-high frequency regions, such as materials for inductor elements or materials for noise filters.

Abstract

Provided is a magnetic powder excellent in high frequency characteristics with low iron loss and excellent efficiency even when a high frequency is applied. The present invention relates to an α-Fe-containing rare earth element-iron-nitrogen magnetic powder comprising: a core region including a rare earth element R (where R is at least one type selected from the group consisting of Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Sm and if Sm is included, Sm is less than 50 atom% with respect to the R component as a whole), Fe, and N; and, on the outside of the core region, an α-Fe-containing region including α-Fe and at least one type selected from the group consisting of an oxide, a nitride, and an oxynitride of the rare earth element R.

Description

α－Ｆｅ含有希土類－鉄－窒素系磁性粉体、その製造方法、磁場増幅用磁性材料、超高周波吸収用磁性材料α-Fe-containing rare earth-iron-nitrogen magnetic powder, manufacturing method thereof, magnetic material for magnetic field amplification, magnetic material for ultra-high frequency absorption
　本開示は、α－Ｆｅ含有希土類－鉄－窒素系磁性粉体、その製造方法、磁場増幅用磁性材料、超高周波吸収用磁性材料に関する。 The present disclosure relates to an α-Fe-containing rare earth-iron-nitrogen magnetic powder, a method for producing the same, a magnetic material for magnetic field amplification, and a magnetic material for absorbing ultra-high frequencies.
　近年、機器の小型多機能化や演算処理速度の高速化に伴って、駆動周波数の高周波化が進展しており、高周波や超高周波を利用した機器の普及は拡大の一途を辿っている。特に、注目されるのは、１ＭＨｚ以上１ＧＨｚ未満までの高周波数領域で利用されるパワーデバイスの進展である。例えば、ＧａＮ電子デバイスは高周波・高出力の無線用やパワーエレクトロニクス用デバイスとして今後大きく市場が伸長すると予測されている。パワーエレクトロニクス用ＧａＮ回路の高周波化にはＧａＮデバイスのみならず、併せて受動部品の高周波化が必要になる。例えば、ＧａＮ非接触給電では扱う周波数が１０ＭＨｚを超えてくるため、高周波に追従できる磁芯材料を用いたコイルが必要である。しかし、現状では高周波特性に優れた磁芯材料が無いために、空芯コイルを使用せざるを得ず、ＧａＮを適用し高周波化してデバイスを小型化することができても、全体の回路サイズが増大するという問題がある。 In recent years, as devices have become smaller and more multi-functional and their arithmetic processing speeds have increased, drive frequencies have become higher, and devices that use high frequencies and ultra-high frequencies are becoming more and more popular. Particularly noteworthy is the development of power devices used in the high frequency range from 1 MHz to less than 1 GHz. For example, the market for GaN electronic devices is expected to grow significantly in the future as high-frequency, high-power wireless and power electronics devices. To increase the frequency of GaN circuits for power electronics, it is necessary to increase the frequency of not only GaN devices but also passive components. For example, since the frequency handled by GaN contactless power supply exceeds 10 MHz, a coil using a magnetic core material that can follow high frequencies is required. However, as there is currently no magnetic core material with excellent high-frequency characteristics, air-core coils have no choice but to be used. There is a problem in that the amount increases.
　次に注目されるのは、１ＧＨｚ～１ＴＨｚまでの超高周波領域における情報インフラの進展である。５Ｇでは１ＧＨｚ以上１０ＧＨｚ未満、５Ｇプラスでは１０ＧＨｚ以上１００ＧＨｚ未満、６Ｇでは１００ＧＨｚ以上１ＴＨｚ以下の領域の信号やその高調波などのスプリアスを吸収する材料の高周波特性に対する様々なニーズがあり、昨今その必要性が高まっている。特に１ＧＨｚ以上さらに１０ＧＨｚ以上で広帯域の超高周波を吸収する材料が現状存在せず、１ＧＨｚ以上１ＴＨｚ以下の領域で幅広く使用できる超広周波数帯域超高周波吸収材料の出現に大きな期待が寄せられている。これまでの高周波用磁性材料の一例としては、粉体表面にフェライト系磁性材料を被覆した希土類－鉄－窒素系磁性材料が知られている（特許文献１）。 The next thing to focus on is the progress of information infrastructure in the ultra-high frequency range from 1 GHz to 1 THz. There are various needs for high-frequency properties of materials that absorb spurious signals such as signals and their harmonics in the range of 1 GHz or more and less than 10 GHz for 5G, 10 GHz or more and less than 100 GHz for 5G Plus, and 100 GHz or more and less than 1 THz for 6G, and the need for this has recently increased. is increasing. In particular, there are currently no materials that absorb ultra-high frequencies in a wide band of 1 GHz or more and 10 GHz or more, and there are great expectations for the emergence of ultra-high frequency absorption materials that can be used widely in the range of 1 GHz or more and 1 THz or less. As an example of a conventional high-frequency magnetic material, a rare earth-iron-nitrogen magnetic material whose powder surface is coated with a ferrite magnetic material is known (Patent Document 1).
国際公開２００８／１３６３９１号明細書International Publication No. 2008/136391
　しかし、特許文献１に開示されている材料は、上記の１ＭＨｚ以上１ＴＨｚ以下までの領域での磁場増幅材料に適用するには効率が十分ではなく、また超高周波領域での超広周波数帯域吸収材ニーズに答えられる高周波特性を有していないという問題がある。 However, the material disclosed in Patent Document 1 does not have sufficient efficiency to be applied as a magnetic field amplification material in the above-mentioned range of 1 MHz to 1 THz, and is not suitable for use as an ultra-wide frequency band absorbing material in the ultra-high frequency range. The problem is that it does not have high frequency characteristics that meet the needs.
　本開示は、高周波を作用させても鉄損が低く優れた効率を有する高周波特性に優れた磁性粉体、およびその製造方法を提供することを目的とする。 An object of the present disclosure is to provide a magnetic powder with excellent high frequency characteristics, which has low core loss and excellent efficiency even when high frequency is applied, and a method for manufacturing the same.
　本開示の一態様にかかるα－Ｆｅ含有希土類－鉄－窒素系磁性粉体は、希土類Ｒ（ＲはＹ、Ｃｅ、Ｐｒ、Ｎｄ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｌｕ、およびＳｍからなる群から選択される少なくとも１種であって、Ｓｍを含む場合はＲ成分全体に対してＳｍが５０原子％未満である）、Ｆｅ、およびＮを含むコア領域と、前記コア領域の外側に、α－Ｆｅ、ならびに前記希土類Ｒの酸化物、窒化物、および酸窒化物からなる群から選択される少なくとも１種を含むα－Ｆｅ含有領域とを有する。　 The α-Fe-containing rare earth-iron-nitrogen magnetic powder according to one aspect of the present disclosure includes rare earths R (R is Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, and a core region containing at least one member selected from the group consisting of Sm (if Sm is included, Sm is less than 50 atomic % with respect to the entire R component), Fe, and N; An α-Fe-containing region including α-Fe and at least one selected from the group consisting of oxides, nitrides, and oxynitrides of the rare earth R is provided on the outside.　
　また、本開示の一態様にかかるα－Ｆｅ含有希土類－鉄－窒素系磁性粉体は、希土類Ｒ（ＲはＹ、Ｃｅ、Ｐｒ、Ｎｄ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｌｕ、およびＳｍからなる群から選択される少なくとも１種であって、Ｓｍを含む場合はＲ成分全体に対してＳｍが５０原子％未満である）、Ｆｅ、およびＮを含むコア領域と、前記コア領域の外側に、海領域および島領域を含む海－島構造を有し、Ｆｅの原子濃度（％）は島領域の方が海領域よりも高く、希土類ＲおよびＯの原子濃度（％）は島領域の方が海領域よりも低い、α－Ｆｅ含有領域とを有する。 In addition, the α-Fe-containing rare earth-iron-nitrogen magnetic powder according to one aspect of the present disclosure includes rare earths R (R is Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu , and Sm (if Sm is included, Sm is less than 50 atomic % with respect to the entire R component), Fe, and N; Outside the region, it has a sea-island structure including a sea region and an island region, and the atomic concentration (%) of Fe is higher in the island region than in the sea region, and the atomic concentration (%) of rare earths R and O is The island region has a lower α-Fe content region than the sea region.
　また、本開示の一態様にかかるα－Ｆｅ含有希土類－鉄－窒素系磁性粉体の製造方法は、希土類Ｒ（ＲはＹ、Ｃｅ、Ｐｒ、Ｎｄ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｌｕ、およびＳｍからなる群から選択される少なくとも１種であって、Ｓｍを含む場合はＲ成分全体に対してＳｍが５０原子％未満である）、Ｆｅ、およびＮを含む希土類－鉄－窒素系磁性粉体、水、ならびにリン含有物を含むスラリーに対して無機酸を添加することで、希土類－鉄－窒素系磁性粉体上にリン化合物被覆部を形成して、リン化合物被覆部を有する希土類－鉄－窒素系磁性粉体を得るリン処理工程、および前記リン化合物被覆部を有する希土類－鉄－窒素系磁性粉体を、酸素含有雰囲気下で３５０℃以上６００℃以下で熱処理する酸化工程を含む。 Furthermore, the method for producing α-Fe-containing rare earth-iron-nitrogen magnetic powder according to one aspect of the present disclosure includes rare earth R (R is Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Rare earth-iron containing at least one member selected from the group consisting of Tm, Lu, and Sm (if Sm is included, Sm is less than 50 atomic % with respect to the entire R component), Fe, and N - By adding an inorganic acid to a slurry containing nitrogen-based magnetic powder, water, and phosphorus-containing material, a phosphorus compound coating is formed on rare earth-iron-nitrogen-based magnetic powder, thereby forming a phosphorus compound coating. a phosphorus treatment step to obtain a rare earth-iron-nitrogen magnetic powder having a phosphorus compound-coated portion, and a heat treatment of the rare-earth-iron-nitrogen magnetic powder having a phosphorus compound-coated portion at a temperature of 350° C. or more and 600° C. or less in an oxygen-containing atmosphere. This includes an oxidation step.
　本開示によれば、高周波を作用させても鉄損が低く優れた効率を有する高周波特性に優れた磁性粉体、およびその製造方法を提供することができる。 According to the present disclosure, it is possible to provide a magnetic powder with excellent high frequency characteristics, which has low core loss and excellent efficiency even when high frequency is applied, and a method for manufacturing the same.
実施例１～４、比較例１～３で作製した磁性粉体のＸＲＤ分析結果を示す。The results of XRD analysis of the magnetic powders produced in Examples 1 to 4 and Comparative Examples 1 to 3 are shown. 比較例１で作製した磁性粉体断面の表面付近のＳＴＥＭ像、ＳＴＥＭ－ＥＤＸ像を示す。A STEM image and a STEM-EDX image near the surface of a cross section of the magnetic powder produced in Comparative Example 1 are shown. 比較例１で作製した磁性粉体断面の表面付近のライン分析結果を示す。The results of line analysis near the surface of a cross section of the magnetic powder produced in Comparative Example 1 are shown. 実施例１で作製した磁性粉体断面の表面付近のＳＴＥＭ像、ＳＴＥＭ－ＥＤＸ像を示す。1 shows a STEM image and a STEM-EDX image near the surface of a cross section of the magnetic powder produced in Example 1. 実施例１で作製した磁性粉体断面の表面付近のライン分析結果を示す。The results of line analysis near the surface of the cross section of the magnetic powder produced in Example 1 are shown. 実施例２で作製した磁性粉体断面の表面付近のＳＴＥＭ像、ＳＴＥＭ－ＥＤＸ像を示す。A STEM image and a STEM-EDX image near the surface of a cross section of the magnetic powder produced in Example 2 are shown. 実施例２で作製した磁性粉体断面の表面付近のライン分析結果を示す。The results of line analysis near the surface of the cross section of the magnetic powder produced in Example 2 are shown. 実施例２で作製した磁性粉体断面のα－Ｆｅ含有領域全体のＳＴＥＭ像を示す。A STEM image of the entire α-Fe-containing region of the cross section of the magnetic powder produced in Example 2 is shown. 実施例２で作製した磁性粉体断面のα－Ｆｅ含有領域全体のライン分析結果を示す。The results of line analysis of the entire α-Fe-containing region of the cross section of the magnetic powder produced in Example 2 are shown. 実施例４で作製した磁性粉体断面の表面付近のＳＴＥＭ像、ＳＴＥＭ－ＥＤＸ像を示す。A STEM image and a STEM-EDX image of the vicinity of the surface of a cross section of the magnetic powder produced in Example 4 are shown. 実施例４で作製した磁性粉体断面の表面付近のライン分析結果を示す。The results of line analysis near the surface of the cross section of the magnetic powder produced in Example 4 are shown. 実施例４で作製した磁性粉体断面のα－Ｆｅ含有領域全体のＳＴＥＭ－ＥＤＸ像を示す。A STEM-EDX image of the entire α-Fe-containing region of the cross section of the magnetic powder produced in Example 4 is shown. 実施例４で作製した磁性粉体断面のα－Ｆｅ含有領域全体のライン分析結果を示す。The line analysis results of the entire α-Fe-containing region of the cross section of the magnetic powder produced in Example 4 are shown. 実施例４で作製した磁性粉体断面のα－Ｆｅ含有領域全体のＴＥＭ像および電子線回折像を示す。A TEM image and an electron diffraction image of the entire α-Fe-containing region of a cross section of the magnetic powder produced in Example 4 are shown. 実施例１～４、比較例１～３で作製した磁性粉体を用いた磁性材料の、複素比透磁率の周波数依存性を示す。The frequency dependence of the complex relative magnetic permeability of magnetic materials using magnetic powders produced in Examples 1 to 4 and Comparative Examples 1 to 3 is shown. 図３Ａで示した、実施例１の磁性粉体断面の表面付近の拡大図を示す。An enlarged view of the vicinity of the surface of the cross section of the magnetic powder of Example 1 shown in FIG. 3A is shown. 実施例６で作製した磁性粉体を用いた磁性材料の、複素比透磁率の周波数依存性を示す。The frequency dependence of the complex relative magnetic permeability of the magnetic material using the magnetic powder produced in Example 6 is shown.
　以下、本開示の実施形態について詳述する。ただし、以下に示す実施形態は、本開示の技術思想を具体化するための一例であり、本開示を以下のものに限定するものではない。なお、本明細書において「工程」との語は、独立した工程だけではなく、他の工程と明確に区別できない場合であってもその工程の所期の目的が達成されれば、本用語に含まれる。また「～」を用いて示された数値範囲は、「～」の前後に記載される数値をそれぞれ最小値及び最大値として含む範囲を示す。 Hereinafter, embodiments of the present disclosure will be described in detail. However, the embodiment shown below is an example for embodying the technical idea of the present disclosure, and the present disclosure is not limited to the following. Note that in this specification, the term "process" is used not only to refer to an independent process, but also to include a process that cannot be clearly distinguished from other processes as long as the intended purpose of the process is achieved. included. Furthermore, a numerical range indicated using "-" indicates a range that includes the numerical values written before and after "-" as the minimum and maximum values, respectively.
　本明細書において、「高周波」とは、高い周波数を有する電磁波のことであり、本開示では特に断らない限り、特に１ＭＨｚ以上１ＧＨｚ未満の電磁波のことをいうものとする。また、「超高周波」とは「高周波」より高い１ＧＨｚ以上１ＴＨｚ以下の周波数を有する電磁波のことをいうものとする。 In this specification, "high frequency" refers to electromagnetic waves having a high frequency, and in this disclosure, unless otherwise specified, it specifically refers to electromagnetic waves of 1 MHz or more and less than 1 GHz. Furthermore, "super high frequency" refers to electromagnetic waves having a frequency of 1 GHz or more and 1 THz or less, which is higher than "high frequency".
　本明細書において、「優れた効率」とは、ある周波数ｆにおいて、磁性材料の複素比透磁率（μ）の実数項（μ’）に対する虚数項（μ”）の比、即ちｔａｎδ＝μ”／μ’（損失係数ともいう）が小さな値をとることである。δを位相差と言う。また、（９０°－δ）の値を位相角θと言う。従って、「優れた効率」とは、δとは逆にθが大きな値をとり９０°に近い値になることであり、ｔａｎδ及びδが小さい、又はθが大きく９０°に近づくことで、周波数ｆの電磁波の損失を低減しつつ増幅することができる。磁場増幅特性においては、θの値が増加（ｔａｎδおよびδの値が減少）することを「θ（ｔａｎδ）が向上する」といい、一方、θの値が減少（ｔａｎδおよびδの値が増加）することを、磁場増幅特性が「θ（ｔａｎδ）が悪化する」という。 In this specification, "excellent efficiency" means the ratio of the imaginary term (μ'') to the real term (μ') of the complex relative magnetic permeability (μ) of a magnetic material at a certain frequency f, that is, tan δ = μ'' /μ' (also called loss coefficient) takes a small value. δ is called phase difference. Further, the value of (90°-δ) is called the phase angle θ. Therefore, "excellent efficiency" means that θ takes a large value and approaches 90°, contrary to δ, and if tan δ and δ are small or θ is large and approaches 90°, the frequency It is possible to amplify the electromagnetic wave f while reducing its loss. In terms of magnetic field amplification characteristics, an increase in the value of θ (a decrease in the values of tanδ and δ) is referred to as "an improvement in θ (tanδ)"; on the other hand, an increase in the value of θ (an increase in the values of tanδ and δ) ) is said to be "deterioration of θ (tan δ)" in the magnetic field amplification characteristics.
　本明細書において、「磁場増幅」特性とは、磁性材料の複素比透磁率の実数項（μ’）が真空の比透磁率の実数項である１より大きく、磁性材料が置かれた空間の磁場を真空（または大気）の場合に比べ増大させる特性のことである。磁場増幅特性が良い、または、高いとは、μ’が高いことをいい、ある周波数ｆにおいてμ’が２を超える材料のことを（周波数ｆにおける）「磁場増幅用磁性材料」という。単に比透磁率という場合、複素比透磁率の実数項の絶対値並びに虚数項の絶対値のことを総称するものとする。高比透磁率という場合、特に断りがない限り、比透磁率の実数項が高いことをいうものとする。 In this specification, "magnetic field amplification" property means that the real term (μ') of the complex relative magnetic permeability of the magnetic material is larger than 1, which is the real term of the relative magnetic permeability of a vacuum, and the property of the space in which the magnetic material is placed is A property that increases the magnetic field compared to a vacuum (or atmosphere). Good or high magnetic field amplification characteristics means that μ' is high, and a material with μ' exceeding 2 at a certain frequency f is referred to as a "magnetic material for magnetic field amplification" (at frequency f). When simply referred to as relative magnetic permeability, it is a general term for the absolute value of the real term and the absolute value of the imaginary term of complex relative magnetic permeability. High relative magnetic permeability means that the real term of relative magnetic permeability is high unless otherwise specified.
　本明細書において、「超高周波吸収」特性とは、超高周波領域での吸収特性のことをいい、超高周波領域で磁性材料の複素比透磁率の虚数項（μ”）が０より大きく、磁性材料が置かれた空間に入射する高周波を減衰させる特性のことである。ある周波数ｆで超高周波吸収特性が良い、または、高いとは、その周波数ｆでμ”が高いことをいう。また、超高周波領域においてμ”が０を超える材料のことを「超高周波吸収用磁性材料」という。超高周波吸収用磁性材料に限って、μ”が高くなることを「μ”が向上する」、低くなることを「μ”が悪化する」ともいう。また、高周波領域での磁場増幅特性と、超高周波領域での吸収特性を併せて「高周波特性」という。 In this specification, the "ultra-high frequency absorption" property refers to the absorption property in the super-high frequency region, and in the super-high frequency region, the imaginary term (μ'') of the complex relative magnetic permeability of the magnetic material is larger than 0, and the magnetic material It is a property of attenuating high frequency waves incident on a space in which a material is placed. Good or high super high frequency absorption property at a certain frequency f means that μ'' is high at that frequency f. Furthermore, a material whose μ'' exceeds 0 in the ultra-high frequency region is referred to as a "magnetic material for ultra-high frequency absorption." In the case of magnetic materials for ultra-high frequency absorption, an increase in μ'' is also referred to as "improving μ", and a decrease in μ'' is also referred to as "deterioration in μ". Furthermore, the magnetic field amplification characteristics in the high frequency region and the absorption characteristics in the ultra-high frequency region are collectively referred to as "high frequency characteristics."
＜＜α－Ｆｅ含有希土類－鉄－窒素系磁性粉体＞＞
　本実施形態のα－Ｆｅ含有希土類－鉄－窒素系磁性粉体は、希土類Ｒ（ＲはＹ、Ｃｅ、Ｐｒ、Ｎｄ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｌｕ、およびＳｍからなる群から選択される少なくとも１種であって、Ｓｍを含む場合はＲ成分全体に対してＳｍが５０原子％未満である）、Ｆｅ、およびＮを含むコア領域と、コア領域の外側に、α－Ｆｅ、ならびに希土類Ｒの酸化物、窒化物、および酸窒化物からなる群から選択される少なくとも１種を含むα－Ｆｅ含有領域とを有することを特徴とする。 <<Rare earth-iron-nitrogen magnetic powder containing α-Fe>>
The α-Fe-containing rare earth-iron-nitrogen magnetic powder of the present embodiment has rare earth elements R (R is composed of Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Sm). A core region containing at least one member selected from the group consisting of Sm (if Sm is included, Sm is less than 50 atomic % with respect to the entire R component), Fe, and N, and outside the core region, α -Fe, and an α-Fe-containing region containing at least one selected from the group consisting of rare earth R oxides, nitrides, and oxynitrides.
＜コア領域＞
　コア領域は、希土類－鉄－窒素系粉体からなり、具体的には希土類Ｒ（ＲはＹ、Ｃｅ、Ｐｒ、Ｎｄ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｌｕ、およびＳｍからなる群から選択される少なくとも１種であって、Ｓｍを含む場合はＲ成分全体に対してＳｍが５０原子％未満である）、Ｆｅ、およびＮを含む。コア領域は、Ｔｈ２Ｚｎ１７型またはＴｈ２Ｎｉ１７型の結晶構造をもち、一般式がＲｘＦｅ１００－ｘ－ｙＮｙで表されるＲ（ただし、ＲはＹ、Ｃｅ、Ｐｒ、Ｎｄ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｌｕ、Ｓｍの中から選択される少なくとも１種であって、Ｓｍを含む場合は、Ｒ成分全体に対して、Ｓｍが５０原子％未満である）と鉄（Ｆｅ）と窒素（Ｎ）からなる窒化物であってよい。ここで、ｘは、３以上３０以下、ｙは１０以上３０以下、残部が主としてＦｅとされることが好ましい。Ｓｍを含む場合は、Ｒ成分全体に対して、Ｓｍが５０原子％未満であるが、２５原子％以下が好ましく、５原子％以下がより好ましい。 <Core area>
The core region is made of rare earth-iron-nitrogen powder, specifically rare earth R (R is made of Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Sm). At least one selected from the group consisting of Sm (if Sm is included, Sm is less than 50 atomic % with respect to the entire R component), Fe, and N. The core region has a crystal structure of Th 2 Zn 17 type or Th 2 Ni 17 type, and has a general formula of R x Fe 100-xy N y (where R is Y, Ce, Pr, At least one selected from Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Sm, and when Sm is included, Sm is less than 50 atomic % with respect to the entire R component. It may be a nitride consisting of iron (Fe), nitrogen (N), iron (Fe), and nitrogen (N). Here, it is preferable that x is 3 or more and 30 or less, y is 10 or more and 30 or less, and the remainder is mainly Fe. When Sm is included, the Sm content is less than 50 atom %, preferably 25 atom % or less, and more preferably 5 atom % or less, based on the entire R component.
　コア領域を構成する希土類－鉄－窒素系磁性粉体の製造方法は特に限定されず、以下に製造方法の例を詳述する。 The method for manufacturing the rare earth-iron-nitrogen magnetic powder constituting the core region is not particularly limited, and examples of the manufacturing method will be described in detail below.
（固相法）
　固相法による希土類－鉄－窒素系磁性粉体の製造方法は、
Ｒ酸化物粉体とＦｅ原料とＣａ粉体を混合する工程（混合工程）、
得られた混合物を還元する工程（還元工程）、
還元工程で得られた合金粒子を窒化処理する工程（窒化工程）
を含む方法である。 (solid phase method)
The method for producing rare earth-iron-nitrogen magnetic powder using the solid phase method is as follows:
A step of mixing R oxide powder, Fe raw material, and Ca powder (mixing step),
a step of reducing the obtained mixture (reduction step);
Process of nitriding the alloy particles obtained in the reduction process (nitriding process)
This is a method that includes
［混合工程］
　混合工程では、希土類Ｒの酸化物粉体とＦｅ原料とＣａ粉体とを混合することで合金粒子を得る。混合工程において、Ｆｅ原料としては、金属Ｆｅだけでなく、Ｆｅ２Ｏ３及び／又はＦｅ３Ｏ４を使用することもできる。Ｆｅ２Ｏ３及び／又はＦｅ３Ｏ４を使用する場合の含有量（金属Ｆｅ、Ｆｅ２Ｏ３及び／又はＦｅ３Ｏ４に含まれるＦｅの合計モル数に対する、Ｆｅ２Ｏ３及び／又はＦｅ３Ｏ４に含まれるＦｅの合計モル数）は、３０原子％以下が好ましい。これらの酸化鉄がＣａにより還元されるときの反応熱により、全体として均一な反応が進行し、外部エネルギーの節約や収率の向上につながる。粒状のＣａの混合量は、Ｒ酸化物と、選択的に混合する金属酸化物との酸化物を還元するために充分な量であることが必要である。粒状のＣａの混合量としては、Ｒ酸化物と、選択的に混合するＦｅ２Ｏ３及び／又はＦｅ３Ｏ４中に含まれる酸素原子の当量に対し０．５倍以上３倍以下であってよく、１倍以上２倍以下が好ましい。 [Mixing process]
In the mixing step, alloy particles are obtained by mixing rare earth R oxide powder, Fe raw material, and Ca powder. In the mixing step, not only metal Fe but also Fe 2 O 3 and/or Fe 3 O 4 can be used as the Fe raw material. Content when using Fe 2 O 3 and/or Fe 3 O 4 (Fe 2 O 3 and/or relative to the total number of moles of Fe contained in metal Fe, Fe 2 O 3 and/or Fe 3 O 4 ) The total number of moles of Fe contained in Fe 3 O 4 is preferably 30 atomic % or less. Due to the heat of reaction when these iron oxides are reduced by Ca, the reaction progresses uniformly as a whole, leading to saving of external energy and improvement of yield. The amount of granular Ca mixed needs to be sufficient to reduce the oxide of the R oxide and the metal oxide to be selectively mixed. The amount of granular Ca to be mixed is 0.5 times or more and 3 times or less relative to the equivalent amount of oxygen atoms contained in the R oxide and Fe 2 O 3 and/or Fe 3 O 4 to be selectively mixed. It may be 1 time or more and 2 times or less is preferable.
［還元工程］
　混合工程で得られた混合粉を、真空排気が可能な加熱容器中に配置する。加熱容器内を真空排気した後、アルゴンガスを通じながら、６００℃以上１３００℃以下、好ましくは７００℃以上１２００℃以下、より好ましくは８００℃以上１１００℃以下で加熱する。加熱温度が６００℃未満では、酸化物の還元反応が進行せず、加熱温度が１３００℃を超えると、希土類とＦｅが融解して塊状になることがある。また、加熱温度が７００℃以上では、還元時間を短時間とでき生産性が向上する傾向があり、１２００℃以下とすると、Ｃａの飛散を低減でき、還元時のばらつきをより低減できる傾向がある。熱処理時間は、還元反応をより均一に行う観点から、４時間以下であってよく、１２０分未満が好ましく、９０分未満がより好ましく、熱処理時間の下限は１０分以上が好ましく、３０分以上がより好ましい。ここで、金属Ｆｅのほか混合粉にＦｅ２Ｏ３及び／又はＦｅ３Ｏ４が適量含まれている場合、昇温途中で自己発熱し、効率的に均一な反応が進行する。一方で、上述の混合工程のようにＦｅ元素換算で、金属Ｆｅに対して３０原子％を超えるＦｅ２Ｏ３及び／又はＦｅ３Ｏ４が混合されていると、極めて大きな発熱により爆発あるいは飛散が生じることがある。また、還元温度を制御することにより、得られる希土類－鉄－窒素系磁性粉体の粒径を制御することができる。一般に還元温度が高くなるにつれ粉体粒径は大きくなる。 [Reduction process]
The mixed powder obtained in the mixing step is placed in a heating container that can be evacuated. After evacuating the inside of the heating container, it is heated at 600° C. or higher and 1300° C. or lower, preferably 700° C. or higher and 1200° C. or lower, more preferably 800° C. or higher and 1100° C. or lower, while passing argon gas. If the heating temperature is less than 600°C, the reduction reaction of the oxide will not proceed, and if the heating temperature exceeds 1300°C, the rare earth and Fe may melt and form lumps. In addition, when the heating temperature is 700°C or higher, the reduction time tends to be shortened and productivity tends to improve, while when the heating temperature is 1200°C or lower, scattering of Ca can be reduced and variations during reduction tend to be further reduced. . From the viewpoint of performing the reduction reaction more uniformly, the heat treatment time may be 4 hours or less, preferably less than 120 minutes, and more preferably less than 90 minutes, and the lower limit of the heat treatment time is preferably 10 minutes or more, and 30 minutes or more. More preferred. Here, if the mixed powder contains an appropriate amount of Fe 2 O 3 and/or Fe 3 O 4 in addition to metal Fe, self-heating occurs during the temperature rise, and the reaction progresses efficiently and uniformly. On the other hand, if more than 30 atomic % of Fe 2 O 3 and/or Fe 3 O 4 is mixed with respect to the metal Fe as in the above-mentioned mixing process, an explosion or scattering may occur due to extremely large heat generation. may occur. Furthermore, by controlling the reduction temperature, the particle size of the obtained rare earth-iron-nitrogen magnetic powder can be controlled. Generally, as the reduction temperature increases, the powder particle size increases.
［窒化工程］
　窒化工程では、還元工程で得られた合金粒子を窒化する工程である。アルゴンガス中で、好ましくは２５０℃以上８００℃以下、より好ましくは３００℃以上６００℃以下の温度領域まで冷却する。後段の窒化工程で窒化反応物の分解を抑制して反応効率を上げるために、さらに好ましくは４００℃以上５５０℃以下の温度領域まで冷却する。その後、加熱容器を再び真空排気した後、窒素ガスを導入する。導入するガスは窒素に限らず、窒素原子を含むガス、例えば、アンモニアでもよい。大気圧以上の圧力で窒素ガスを通じながら数時間、好適には５時間程度加熱した後、加熱を停止し放冷する。 [Nitriding process]
The nitriding step is a step of nitriding the alloy particles obtained in the reduction step. It is cooled in an argon gas to a temperature range of preferably 250°C or more and 800°C or less, more preferably 300°C or more and 600°C or less. In order to suppress the decomposition of the nitriding reactants in the subsequent nitriding step and increase reaction efficiency, the temperature is preferably cooled to a temperature range of 400° C. or higher and 550° C. or lower. Thereafter, after the heating container is evacuated again, nitrogen gas is introduced. The gas to be introduced is not limited to nitrogen, but may be a gas containing nitrogen atoms, such as ammonia. After heating for several hours, preferably about 5 hours at a pressure higher than atmospheric pressure while passing nitrogen gas, the heating is stopped and allowed to cool.
　窒化工程後に得られる生成物には、希土類－鉄－窒素系磁性粉体に加えて、副生するＣａＯ、未反応の金属カルシウム等が含まれ、これらが複合した焼結塊状態となっている場合がある。その場合は、水洗工程として、この生成物をイオン交換水中に投入して、酸化カルシウム（ＣａＯ）及びその他のカルシウムを含む成分を水酸化カルシウム（Ｃａ（ＯＨ）２）懸濁物として磁性粉体から分離することができる。この水洗工程として、水中での撹拌、静置、上澄み液の除去を数回繰り返してもよい。さらに残留する水酸化カルシウムは、磁性粉体を酢酸等で洗浄して充分に除去してもよい。残存する未反応のＣａが窒化カルシウム（Ｃａ３Ｎ２）となり、除去がより容易となるため、窒素雰囲気での熱処理の後、水洗工程を行うことが好ましい。これにより得られた希土類－鉄－窒素系磁性粉体は粒度分布がよりシャープになる傾向がある。 The product obtained after the nitriding process contains by-product CaO, unreacted metallic calcium, etc. in addition to rare earth-iron-nitrogen magnetic powder, and is in the form of a composite sintered mass. There are cases. In that case, as a water washing step, this product is poured into ion-exchanged water, and calcium oxide (CaO) and other calcium-containing components are converted into a calcium hydroxide (Ca(OH) 2 ) suspension into magnetic powder. can be separated from As this water washing step, stirring in water, standing still, and removal of the supernatant liquid may be repeated several times. Furthermore, residual calcium hydroxide may be sufficiently removed by washing the magnetic powder with acetic acid or the like. Since remaining unreacted Ca becomes calcium nitride (Ca 3 N 2 ) and is easier to remove, it is preferable to perform a water washing step after the heat treatment in a nitrogen atmosphere. The rare earth-iron-nitrogen magnetic powder thus obtained tends to have a sharper particle size distribution.
（沈殿法）
　沈殿法による希土類－鉄－窒素系磁性粉体の製造方法は、
ＲとＦｅを含む溶液と沈殿剤を混合し、ＲとＦｅとを含む沈殿物を得る工程（沈殿工程）、
沈殿物を焼成してＲとＦｅを含む酸化物を得る工程（酸化工程）、
酸化物を、還元性ガス含有雰囲気下で熱処理して部分酸化物を得る工程（前処理工程）、
部分酸化物を還元する工程（還元工程）、および
還元工程で得られた合金粒子を窒化処理する工程（窒化工程）
を含む方法である。 (Precipitation method)
The method for producing rare earth-iron-nitrogen magnetic powder by precipitation method is as follows:
A step of mixing a solution containing R and Fe with a precipitant to obtain a precipitate containing R and Fe (precipitation step);
a step of calcining the precipitate to obtain an oxide containing R and Fe (oxidation step);
a step of heat-treating the oxide in an atmosphere containing a reducing gas to obtain a partial oxide (pretreatment step);
A process of reducing the partial oxide (reduction process) and a process of nitriding the alloy particles obtained in the reduction process (nitriding process)
This is a method that includes
［沈殿工程］
　沈殿工程では、強酸性の溶液に希土類Ｒを含むＲ原料と、鉄Ｆｅを含むＦｅ原料を溶解して、ＲとＦｅを含む溶液を調製する。Ｒ原料、Ｆｅ原料としては、強酸性の溶液に溶解できるものであれば限定されない。例えば、入手のしやすさの点で、Ｒ原料としてはＲ酸化物が、Ｆｅ原料としては硫酸鉄（ＦｅＳＯ４）が挙げられる。ＲとＦｅを含む溶液の濃度は、Ｒ原料とＦｅ原料が実質的に酸性溶液に溶解する範囲で適宜調整することができる。酸性溶液としては溶解性の点で硫酸が挙げられる。 [Precipitation process]
In the precipitation step, a solution containing R and Fe is prepared by dissolving an R raw material containing a rare earth element R and an Fe raw material containing iron Fe in a strongly acidic solution. The R raw material and Fe raw material are not limited as long as they can be dissolved in a strongly acidic solution. For example, in terms of availability, R oxide may be used as the R raw material, and iron sulfate (FeSO 4 ) may be used as the Fe raw material. The concentration of the solution containing R and Fe can be adjusted as appropriate within a range where the R raw material and Fe raw material are substantially dissolved in the acidic solution. Examples of acidic solutions include sulfuric acid in terms of solubility.
　ＲとＦｅを含む溶液と沈殿剤を反応させることにより、ＲとＦｅを含む不溶性の沈殿物を得る。ここで、ＲとＦｅを含む溶液は、沈殿剤との反応時にＲとＦｅを含む溶液となっていればよく、たとえばＲを含む原料とＦｅを含む原料を別々の溶液として調製し、各々の溶液を滴下して沈殿剤と反応させても良い。別々の溶液として調製する場合においても各原料が実質的に酸性溶液に溶解する範囲で適宜調整する。沈殿剤としては、アルカリ性の溶液でＲとＦｅを含む溶液と反応して沈殿物が得られるものであれば限定されず、アンモニア水、苛性ソーダなどが挙げられ、苛性ソーダが好ましい。 By reacting a solution containing R and Fe with a precipitant, an insoluble precipitate containing R and Fe is obtained. Here, the solution containing R and Fe only needs to be a solution containing R and Fe at the time of reaction with the precipitant. For example, the raw material containing R and the raw material containing Fe are prepared as separate solutions, and each The solution may be added dropwise to react with the precipitant. Even in the case of preparing separate solutions, each raw material is appropriately adjusted within the range that it is substantially dissolved in the acidic solution. The precipitant is not limited as long as it reacts with an alkaline solution containing R and Fe to form a precipitate, and examples thereof include aqueous ammonia and caustic soda, with caustic soda being preferred.
　沈殿物を分離した後は、続く酸化工程の熱処理において残存する溶媒に沈殿物が再溶解して、溶媒が蒸発する際に沈殿物が凝集したり、粒度分布、粉体粒径等が変化したりすることを抑制するために、分離物を脱溶媒しておくことが好ましい。脱溶媒する方法として具体的には、例えば溶媒として水を使用する場合、７０℃以上２００℃以下のオーブン中で５時間以上１２時間以下乾燥する方法が挙げられる。 After separating the precipitate, the precipitate is redissolved in the remaining solvent during the heat treatment in the subsequent oxidation process, and when the solvent evaporates, the precipitate may aggregate or the particle size distribution, powder particle size, etc. may change. In order to prevent the separation from occurring, it is preferable to remove the solvent from the separated product. Specifically, as a method for removing the solvent, when using water as a solvent, for example, a method of drying in an oven at 70° C. or higher and 200° C. or lower for 5 hours or more and 12 hours or less can be mentioned.
　沈殿工程の後に、得られる沈殿物を分離洗浄する工程を含んでもよい。洗浄する工程は上澄み溶液の導電率が５ｍＳ／ｍ以下となるまで適宜行う。沈殿物を分離する工程としては、例えば、得られた沈殿物に溶媒（好ましくは水）を加えて混合した後、濾過法、デカンテーション法等を用いることができる。 After the precipitation step, a step of separating and washing the obtained precipitate may be included. The washing step is carried out as appropriate until the conductivity of the supernatant solution becomes 5 mS/m or less. As the step of separating the precipitate, for example, after adding and mixing a solvent (preferably water) to the obtained precipitate, a filtration method, a decantation method, etc. can be used.
［酸化工程］
　酸化工程とは、沈殿工程で形成された沈殿物を焼成することにより、ＲとＦｅとを含む酸化物を得る工程である。例えば、熱処理により沈殿物を酸化物に変換することができる。沈殿物を熱処理する場合、酸素の存在下で行われる必要があり、例えば、大気雰囲気下で行うことができる。また、酸素存在下で行われる必要があるため、沈殿物中の非金属部分に酸素原子を含むことが好ましい。酸化工程における熱処理温度（以下、酸化温度）は特に限定されないが、７００℃以上１３００℃以下が好ましく、９００℃以上１２００℃以下がより好ましい。７００℃未満では酸化が不十分となり、１３００℃を超えると、目的とする希土類－鉄－窒素系磁性粉体の形状、平均粒径および粒度分布が得られない傾向にある。熱処理時間も特に限定されないが、０．５時間以上４時間以下であってよく、１時間以上３時間以下が好ましい。 [Oxidation process]
The oxidation step is a step of obtaining an oxide containing R and Fe by firing the precipitate formed in the precipitation step. For example, heat treatment can convert the precipitate into an oxide. When heat-treating the precipitate, it needs to be carried out in the presence of oxygen, and can be carried out, for example, under an atmospheric atmosphere. Furthermore, since it is necessary to carry out the process in the presence of oxygen, it is preferable that the nonmetallic portion of the precipitate contains oxygen atoms. The heat treatment temperature in the oxidation step (hereinafter referred to as oxidation temperature) is not particularly limited, but is preferably 700°C or more and 1300°C or less, more preferably 900°C or more and 1200°C or less. If it is less than 700°C, oxidation will be insufficient, and if it exceeds 1300°C, the desired shape, average particle size, and particle size distribution of the rare earth-iron-nitrogen magnetic powder will tend not to be obtained. The heat treatment time is also not particularly limited, but may be 0.5 hours or more and 4 hours or less, preferably 1 hour or more and 3 hours or less.
［前処理工程］
　前処理工程とは、ＲとＦｅを含む酸化物を、還元性ガス含有雰囲気下で熱処理することにより、酸化物の一部が還元された部分酸化物を得る工程である。 [Pre-treatment process]
The pretreatment step is a step of heat-treating an oxide containing R and Fe in an atmosphere containing a reducing gas to obtain a partial oxide in which a portion of the oxide is reduced.
［還元工程］
　還元工程とは、部分酸化物を、還元剤の存在下、６００℃以上１３００℃以下、好ましくは、７００℃以上１２００℃以下、より好ましくは８００℃以上１１００℃以下で加熱することで合金粒子を得る工程である。加熱温度が６００℃未満では、酸化物の還元反応が進行せず、加熱温度が１３００℃を超えるとＲとＦｅが融解して塊状になることがある。また、加熱温度が７００℃以上である場合には、還元時間を短時間とでき生産性が向上する傾向があり、１２００℃以下とすると、還元剤であるＣａの飛散を低減でき、還元時のばらつきをより低減できる傾向がある。この還元温度を制御することにより、希土類－鉄－窒素系磁性粉体の粒径を制御することができ、一般に還元温度が高くなるにつれ粉体粒径は大きくなる。熱処理時間は、還元反応をより均一に行う観点から、１２０分未満が好ましく、９０分未満がより好ましく、熱処理時間の下限は１０分以上が好ましく、３０分以上がより好ましい。 [Reduction process]
The reduction step refers to heating the partial oxide at a temperature of 600°C or more and 1300°C or less, preferably 700°C or more and 1200°C or less, more preferably 800°C or more and 1100°C or less, in the presence of a reducing agent to reduce the alloy particles. This is the process of obtaining If the heating temperature is less than 600°C, the reduction reaction of the oxide will not proceed, and if the heating temperature exceeds 1300°C, R and Fe may melt and form a lump. In addition, when the heating temperature is 700°C or higher, the reduction time can be shortened and productivity tends to improve. When the heating temperature is 1200°C or lower, the scattering of Ca, which is a reducing agent, can be reduced, and the reduction time can be reduced. There is a tendency for variations to be further reduced. By controlling this reduction temperature, the particle size of the rare earth-iron-nitrogen magnetic powder can be controlled, and generally, the higher the reduction temperature, the larger the powder particle size. From the viewpoint of performing the reduction reaction more uniformly, the heat treatment time is preferably less than 120 minutes, more preferably less than 90 minutes, and the lower limit of the heat treatment time is preferably 10 minutes or more, and more preferably 30 minutes or more.
［窒化工程］
　窒化工程とは、還元工程で得られた合金粒子を窒化処理することにより、異方性の磁性粉体を得る工程である。前述の沈殿工程で得られる粒子状の沈殿物を用いていることから、還元工程にて多孔質塊状の合金粒子が得られる。これにより、粉砕処理を行うことなく直ちに窒素雰囲気中で熱処理して窒化することができるため、窒化を均一に行うことができる。 [Nitriding process]
The nitriding process is a process of obtaining anisotropic magnetic powder by nitriding the alloy particles obtained in the reduction process. Since the particulate precipitate obtained in the above-mentioned precipitation step is used, porous massive alloy particles can be obtained in the reduction step. As a result, nitriding can be performed immediately by heat treatment in a nitrogen atmosphere without performing a pulverization process, so that nitriding can be performed uniformly.
　合金粒子の窒化処理における熱処理温度（以下、窒化温度）は、好ましくは２５０℃以上８００℃以下、より好ましくは３００℃以上６００℃以下である。また、後段の窒化工程で窒化反応物の分解を抑制して反応効率を上げるために、特に好ましくは４００℃以上５５０℃以下の温度とし、この温度範囲で雰囲気を窒素雰囲気に置換することにより行われる。熱処理時間は、合金粒子の窒化が充分に均一に行われる程度に設定されればよい。 The heat treatment temperature (hereinafter referred to as nitriding temperature) in the nitriding treatment of the alloy particles is preferably 250°C or more and 800°C or less, more preferably 300°C or more and 600°C or less. In addition, in order to suppress the decomposition of the nitriding reactants in the subsequent nitriding step and increase reaction efficiency, the temperature is particularly preferably set to 400°C or more and 550°C or less, and the atmosphere is replaced with a nitrogen atmosphere within this temperature range. be exposed. The heat treatment time may be set to such an extent that the alloy particles are sufficiently uniformly nitrided.
＜α－Ｆｅ含有領域＞　
　α－Ｆｅ含有領域はコア領域の外側に存在する。α－Ｆｅ含有領域は、α－Ｆｅ、ならびに希土類Ｒの酸化物、窒化物、および酸窒化物からなる群から選択される少なくとも１種を含む。α－Ｆｅ含有領域は、希土類Ｒの酸化物、または酸窒化物を含むことが好ましい。希土類Ｒの酸化物、窒化物、酸窒化物は、例えば希土類ＲがＮｄである場合には、それぞれ、酸化ネオジム、窒化ネオジム、酸窒化ネオジムである。α－Ｆｅ含有領域は、隣り合う磁性粒子間の絶縁性を高め、粒間をまたぐ渦電流による鉄損を低減することで、高周波領域のｔａｎδ及び位相角θがより向上し、より高効率の磁場増幅用磁性材料が得られる。α－Ｆｅ含有領域は、磁気的連結を損なわない程度に、さらに、希土類Ｒおよび鉄を含む複酸化物、複窒化物、複酸窒化物などを含んでいてもよい。これらの複酸化物、複窒化物、複酸窒化物は、ペロブスカイト構造やスピネル構造を持つものであってもよい。また、α－Ｆｅ含有領域は、隣り合う磁性粒子を磁気的に連結し、反磁界を減少することにより、磁場増幅用磁性材料の透磁率の実数項μ’がより向上する傾向がある。 <α-Fe containing region>
The α-Fe containing region is present outside the core region. The α-Fe-containing region contains α-Fe and at least one selected from the group consisting of rare earth R oxides, nitrides, and oxynitrides. Preferably, the α-Fe-containing region contains an oxide or oxynitride of rare earth R. The oxide, nitride, and oxynitride of the rare earth R are neodymium oxide, neodymium nitride, and neodymium oxynitride, respectively, when the rare earth R is Nd, for example. The α-Fe-containing region improves the insulation between adjacent magnetic particles and reduces iron loss caused by eddy currents that cross between grains, thereby further improving tan δ and phase angle θ in the high frequency region, resulting in higher efficiency. A magnetic material for magnetic field amplification is obtained. The α-Fe-containing region may further contain a double oxide, a double nitride, a double oxynitride, or the like containing rare earth R and iron, to the extent that magnetic coupling is not impaired. These double oxides, double nitrides, and double oxynitrides may have a perovskite structure or a spinel structure. Furthermore, the α-Fe-containing region magnetically connects adjacent magnetic particles and reduces the demagnetizing field, thereby tending to further improve the real number term μ' of magnetic permeability of the magnetic material for magnetic field amplification.
　α－Ｆｅ含有領域は、希土類Ｒの酸化物、窒化物、および酸窒化物からなる群から選択される少なくとも１種からなるナノ結晶、ならびにα－Ｆｅからなるナノ結晶を含むことが好ましい。これらのナノ結晶を含むことにより、電気的絶縁と磁気的連結の効果がより大きくなることが考えられる。ここでいう「電気的絶縁」とは、電気抵抗の高いα－Ｆｅ含有領域などが磁性粉体の表面に存在することにより、隣り合う磁性粒子同士のコア領域間の導通を遮断することで、コア領域間をまたぐ渦電流の発生を防ぐことをいう。この電気的絶縁により渦電流損失を抑えられて「優れた効率」が達成される。また、ここでいう「磁気的連結」とは、電気抵抗は高いが強磁性を有するα－Ｆｅ含有領域などが磁性粉体表面に存在することにより、隣り合うコア領域間に強磁性結合や静磁気結合を生じさせることを指す。この磁気的連結により、局所的な反磁界を減少させ、コア領域に作用する反磁界が弱まることから高比透磁率を達成できる。上述の効果を実現するために、α－Ｆｅ含有領域は、コア領域の外側にα－Ｆｅ含有領域層として存在することが好ましい。 The α-Fe-containing region preferably includes nanocrystals made of at least one selected from the group consisting of rare earth R oxides, nitrides, and oxynitrides, and nanocrystals made of α-Fe. It is thought that by including these nanocrystals, the effects of electrical insulation and magnetic coupling become greater. "Electrical insulation" here refers to the presence of α-Fe-containing regions with high electrical resistance on the surface of the magnetic powder, which blocks electrical conduction between the core regions of adjacent magnetic particles. This refers to preventing the generation of eddy currents that cross between core regions. This electrical isolation reduces eddy current losses and achieves "superior efficiency." In addition, "magnetic coupling" here refers to the presence of α-Fe-containing regions, which have high electrical resistance but ferromagnetism, on the surface of the magnetic powder, resulting in ferromagnetic coupling and static electricity between adjacent core regions. Refers to creating magnetic coupling. This magnetic coupling reduces the local demagnetizing field and achieves high relative permeability because the demagnetizing field acting on the core region is weakened. In order to achieve the above-mentioned effects, the α-Fe-containing region is preferably present as an α-Fe-containing region layer outside the core region.
　α－Ｆｅ含有領域に含まれる希土類Ｒの酸化物、窒化物、および酸窒化物からなる群から選択される少なくとも１種からなるナノ結晶は、平均粒子径が１ｎｍ以上１０００ｎｍ未満であることが好ましく、１ｎｍ以上１００ｎｍ以下であることがより好ましく、１ｎｍ以上２０ｎｍ以下であることがさらに好ましく、１ｎｍ以上１０ｎｍ以下であることが特に好ましい。α－Ｆｅからなるナノ結晶は、平均粒子径が１ｎｍ以上１０００ｎｍ未満であることが好ましく、１ｎｍ以上１００ｎｍ以下であることがより好ましく、１ｎｍ以上２０ｎｍ以下であることがさらに好ましく、１ｎｍ以上１０ｎｍ以下であることが特に好ましい。これらのナノ結晶の粒子径は、α－Ｆｅ含有希土類－鉄－窒素系磁性粉体の断面のＴＥＭ（透過電子顕微鏡）、もしくはＳＴＥＭ（走査型透過電子顕微鏡）、もしくはＥＤＸ（エネルギー分散型Ｘ線分析）により測定できる。 The nanocrystals made of at least one selected from the group consisting of oxides, nitrides, and oxynitrides of rare earth R contained in the α-Fe-containing region preferably have an average particle size of 1 nm or more and less than 1000 nm. , more preferably 1 nm or more and 100 nm or less, even more preferably 1 nm or more and 20 nm or less, particularly preferably 1 nm or more and 10 nm or less. The average particle diameter of the α-Fe nanocrystals is preferably 1 nm or more and less than 1000 nm, more preferably 1 nm or more and 100 nm or less, even more preferably 1 nm or more and 20 nm or less, and 1 nm or more and 10 nm or less. It is particularly preferable that there be. The particle size of these nanocrystals can be determined by TEM (transmission electron microscopy), STEM (scanning transmission electron microscopy), or EDX (energy dispersive X-ray analysis).
　また、α－Ｆｅからなるナノ結晶の結晶子径は、結晶子径が１ｎｍ以上１００ｎｍ以下の場合において、粉末Ｘ線回折法により測定した（１１０）面におけるピークの半値幅を使用し、シェラーの式Ｄ＝Ｋλ／βｃｏｓθ（Ｋ：シェラー定数０．９、λ：Ｘ線波長（ｎｍ）、β：回折ピークの半値幅（ラジアン）、θ：回折角（ラジアン））から算出することができる。例えば、Ｘ線源はＣｕＫα、４０ｋＶ、２０ｍＡで、１０＜２θ＜９０の間でステップ幅２θ＝０．０２で測定することによりα－Ｆｅからなるナノ結晶の半値幅を求められる。例えば、λが０．１５４ｎｍとなる波長で測定したものを用いる。 In addition, the crystallite diameter of nanocrystals made of α-Fe is determined by using the half-width of the peak in the (110) plane measured by powder X-ray diffraction method when the crystallite diameter is 1 nm or more and 100 nm or less. It can be calculated from the formula D=Kλ/β cos θ (K: Scherrer constant 0.9, λ: X-ray wavelength (nm), β: half width of diffraction peak (radian), θ: diffraction angle (radian)). For example, the half-width of a nanocrystal made of α-Fe can be determined by measuring with an X-ray source of CuKα, 40 kV, and 20 mA, and a step width of 2θ=0.02 in the range 10<2θ<90. For example, a wavelength measured at a wavelength where λ is 0.154 nm is used.
　α－Ｆｅ含有領域全体におけるＦｅの原子濃度（原子％）は２５％以上が好ましく、５０％以上がより好ましい。Ｆｅの原子濃度の上限は特に限定されないが、８０％以下であってもよい。Ｆｅの原子濃度が２５％以上であると磁気的連結が保たれることで、反磁界が小さくなって透磁率が上がる傾向がある。 The atomic concentration (atomic %) of Fe in the entire α-Fe containing region is preferably 25% or more, more preferably 50% or more. The upper limit of the Fe atomic concentration is not particularly limited, but may be 80% or less. When the atomic concentration of Fe is 25% or more, magnetic coupling is maintained, the demagnetizing field decreases, and magnetic permeability tends to increase.
　α－Ｆｅ含有領域全体における希土類Ｒの原子濃度（原子％）は２％以上５０％以下が好ましく、５％以上３０％以下がより好ましい。α－Ｆｅ含有領域全体における窒素の原子濃度（原子％）は０％以上５０％以下が好ましく、０．０１％以上３０％以下がより好ましい。α－Ｆｅ含有領域全体における酸素の原子濃度（原子％）は０％以上５５％以下が好ましく、０．０１％以上３０％以下がより好ましい。α－Ｆｅ含有領域における各元素の原子濃度は、ＳＴＥＭ－ＥＤＸライン分析における各領域中の原子濃度を平均することにより求められる。 The atomic concentration (atomic %) of rare earth R in the entire α-Fe containing region is preferably 2% or more and 50% or less, more preferably 5% or more and 30% or less. The atomic concentration (atomic %) of nitrogen in the entire α-Fe containing region is preferably 0% or more and 50% or less, more preferably 0.01% or more and 30% or less. The atomic concentration (atomic %) of oxygen in the entire α-Fe containing region is preferably 0% or more and 55% or less, more preferably 0.01% or more and 30% or less. The atomic concentration of each element in the α-Fe containing region is determined by averaging the atomic concentration in each region in STEM-EDX line analysis.
　α－Ｆｅ含有領域全体におけるＯの平均原子濃度（原子％）はコア領域のＯの平均原子濃度（原子％）より高いことが好ましい。α－Ｆｅ含有領域におけるＯの平均原子濃度は、コア領域中のＯの平均原子濃度の１．０５倍以上とすることが好ましく、１．５倍以上がより好ましく、２倍以上がさらに好ましく、４倍以上が特に好ましい。また、α－Ｆｅ含有領域中のＲの平均原子濃度はコア領域中のＲの平均原子濃度の２倍以下であり、１．９倍以下が好ましく、１．８倍以下がより好ましい。α－Ｆｅ含有領域中のＲの平均原子濃度は、コア領域中のＲの平均原子濃度の０．１倍以上であってよく、０．５倍以上であることが好ましい。ここでの特定元素の「平均原子濃度」とは、α－Ｆｅ含有希土類－鉄－窒素系磁性粉体において、コア領域からα－Ｆｅ含有領域の最表面まで厚み方向に貫く１本または複数本の線分上で、ＳＴＥＭ－ＥＤＸライン分析を行い、５０点以上の元素Ｘの原子濃度の測定値を得て、それらを平均した原子濃度のことである。　 The average atomic concentration (atomic %) of O in the entire α-Fe-containing region is preferably higher than the average atomic concentration (atomic %) of O in the core region. The average atomic concentration of O in the α-Fe-containing region is preferably 1.05 times or more, more preferably 1.5 times or more, even more preferably 2 times or more, as the average atomic concentration of O in the core region. Particularly preferred is 4 times or more. Further, the average atomic concentration of R in the α-Fe-containing region is at most twice the average atomic concentration of R in the core region, preferably at most 1.9 times, and more preferably at most 1.8 times. The average atomic concentration of R in the α-Fe containing region may be 0.1 times or more, preferably 0.5 times or more, the average atomic concentration of R in the core region. Here, the "average atomic concentration" of a specific element refers to one or more particles that penetrate in the thickness direction from the core region to the outermost surface of the α-Fe-containing region in the α-Fe-containing rare earth-iron-nitrogen magnetic powder. STEM-EDX line analysis is performed on the line segment to obtain measured values of the atomic concentration of element X at 50 or more points, and the atomic concentration is the average of these measurements.　
　α－Ｆｅ含有領域の厚みは、α－Ｆｅ含有希土類－鉄－窒素系磁性粉体の平均粒径の０．０１％以上５０％未満であることが好ましく、０．０１％以上４５％以下であることがより好ましく、０．０１％以上３５％以下であることがさらに好ましく、０．５％以上２０％以下が特に好ましい。０．００１％以上とすることで電気的絶縁性が向上する傾向がある。５０％未満の場合、希土類Ｒ、Ｆｅ、およびＮを含むコア領域の存在により、μ’が大きくなる傾向がある。 The thickness of the α-Fe-containing region is preferably 0.01% or more and less than 50%, and 0.01% or more and 45% or less of the average particle size of the α-Fe-containing rare earth-iron-nitrogen magnetic powder. It is more preferably at least 0.01% and at most 35%, particularly preferably at least 0.5% and at most 20%. When the content is 0.001% or more, electrical insulation tends to improve. If it is less than 50%, μ' tends to increase due to the presence of the core region containing rare earth elements R, Fe, and N.
　α－Ｆｅ含有領域の厚みは１ｎｍ以上１０μｍ以下であることが好ましく、１０ｎｍ以上５μｍ以下であることがより好ましい。また、高周波領域のμ’向上の観点では、５０ｎｍ以上１μｍ以下がさらに好ましい。１ｎｍ以上とすることで電気的絶縁性が向上する傾向がある。１０μｍ以下であるとコア領域の存在により、μ’が大きくなる傾向がある。α－Ｆｅ含有領域の厚みは、α－Ｆｅ含有希土類－鉄－窒素系磁性粉体の断面のＴＥＭ、ＳＴＥＭ又はＦＥ－ＳＥＭ観察像において、ＴＥＭ像および二次電子・反射電子像もしくはＥＤＸによるライン分析或いは面分析、さらに十分な測定点数を実施した点分析によって組成分析を行うことにより測定できる。 The thickness of the α-Fe containing region is preferably 1 nm or more and 10 μm or less, more preferably 10 nm or more and 5 μm or less. Further, from the viewpoint of improving μ' in the high frequency region, the thickness is more preferably 50 nm or more and 1 μm or less. Electrical insulation tends to improve when the thickness is 1 nm or more. If it is 10 μm or less, μ' tends to increase due to the presence of the core region. The thickness of the α-Fe-containing region is determined by the line in the TEM, STEM, or FE-SEM observation image of the cross section of the α-Fe-containing rare earth-iron-nitrogen magnetic powder. It can be measured by performing compositional analysis by analysis or surface analysis, or point analysis using a sufficient number of measurement points.
　α－Ｆｅ含有領域によるコア領域の表面被覆率は１０％以上が好ましく、５０％以上がより好ましく、８０％以上がさらに好ましく、１００％が特に好ましい。コア領域の表面被覆率を高めることにより、電気的絶縁を高め、ｔａｎδや位相角θを向上させる効果があり、特に表面被覆率が１００％のときには、磁性粉体の電気的孤立がより促進され、上記効果をさらに高めることができる。α－Ｆｅ含有領域によるコア領域の表面被覆率は、粉体の断面を、ＥＤＸが備えられたＴＥＭ、ＳＴＥＭ又はＦＥ－ＳＥＭで観測して測定することができ、観察されるコア領域の全体周長に対するα－Ｆｅ含有領域とコア領域との接触部分の長さの比を「表面被覆率」と定義する。この際、上述の方法で観察される画像の中から２０個から５０個の磁性粉体の断面を測定し、平均した値を表面被覆率とすることが好ましい。 The surface coverage of the core region by the α-Fe containing region is preferably 10% or more, more preferably 50% or more, even more preferably 80% or more, and particularly preferably 100%. Increasing the surface coverage of the core region has the effect of increasing electrical insulation and improving tan δ and phase angle θ. Especially when the surface coverage is 100%, electrical isolation of the magnetic powder is further promoted. , the above effects can be further enhanced. The surface coverage of the core region by the α-Fe-containing region can be measured by observing a cross section of the powder using a TEM, STEM, or FE-SEM equipped with EDX. The ratio of the length of the contact portion between the α-Fe-containing region and the core region to the length is defined as “surface coverage”. At this time, it is preferable to measure the cross sections of 20 to 50 magnetic powders from among the images observed by the above-mentioned method, and take the average value as the surface coverage.
　α－Ｆｅ含有希土類－鉄－窒素系磁性粉体において、コア領域が希土類－鉄－窒素系化合物を含み、ＸＲＤ回折パターンにおいて、α－Ｆｅの（１１０）面の回折ピーク強度（Ｉ）とコア領域の希土類－鉄－窒素系化合物の最強線のピーク強度（ＩＩ）との比（Ｉ）／（ＩＩ）が０．０１以上１０未満であることが好ましく、０．０２以上５未満であることがより好ましく、０．１以上２以下であることがさらに好ましい。α－Ｆｅの（１１０）面の回折ピーク強度（Ｉ）は、α－Ｆｅの存在量を表しており、前述した比（Ｉ）／（ＩＩ）が０．０１以上１０未満であるときに、磁性粒子間の磁気的連結及び電気的絶縁を両立できる傾向がある。比（Ｉ）／（ＩＩ）が０．０１以上であると、特定の厚みのα―Ｆｅ分離相を有することで、電気的絶縁性が向上し、μ’を大きくできる傾向がある。比（Ｉ）／（ＩＩ）が１０未満であると、電気的絶縁が向上しつつ、コア領域の体積分率も大きくなるために、μ’が大きくなる傾向がある。なお、ＸＲＤ回折パターンにおける回折ピーク強度は、粉末Ｘ線結晶回折装置にて測定を行い、測定したα－Ｆｅの（１１０）面の回折ピーク強度を、コア領域を構成する希土類－鉄－窒素系化合物の最強線のピーク強度で除して求められる。例えば、Ｘ線源はＣｕＫα、４０ｋＶ、２０ｍＡで、１０＜２θ＜９０の間でステップ幅２θ＝０．０２で測定することにより求められる。希土類－鉄－窒素系化合物の最強線は、Ｔｈ２Ｚｎ１７型結晶（菱面晶系）の場合には（３０３）面であり、Ｔｈ２Ｎｉ１７型結晶（六方晶系）の場合には（３０２）面である。 In α-Fe-containing rare earth-iron-nitrogen magnetic powder, the core region contains a rare earth-iron-nitrogen compound, and in the XRD diffraction pattern, the diffraction peak intensity (I) of the (110) plane of α-Fe and the core The ratio (I)/(II) to the peak intensity (II) of the strongest line of the rare earth-iron-nitrogen compound in the region is preferably 0.01 or more and less than 10, and preferably 0.02 or more and less than 5. is more preferable, and even more preferably 0.1 or more and 2 or less. The diffraction peak intensity (I) of the (110) plane of α-Fe represents the amount of α-Fe present, and when the ratio (I)/(II) mentioned above is 0.01 or more and less than 10, There is a tendency to achieve both magnetic coupling and electrical insulation between magnetic particles. When the ratio (I)/(II) is 0.01 or more, having an α-Fe separated phase with a specific thickness tends to improve electrical insulation and increase μ'. When the ratio (I)/(II) is less than 10, the electrical insulation is improved and the volume fraction of the core region is also increased, so μ' tends to become large. The diffraction peak intensity in the XRD diffraction pattern is measured using a powder X-ray crystal diffractometer, and the diffraction peak intensity of the (110) plane of α-Fe is the rare earth-iron-nitrogen system constituting the core region. It is calculated by dividing by the peak intensity of the strongest line of the compound. For example, the X-ray source is CuKα, 40 kV, 20 mA, and is determined by measuring in the range 10<2θ<90 with a step width 2θ=0.02. The strongest line of rare earth-iron-nitrogen compounds is the (303) plane in the case of Th 2 Zn 17 type crystal (rhombohedral system), and the strongest line in the case of Th 2 Ni 17 type crystal (hexagonal system). It is a (302) plane.
　α－Ｆｅ含有領域は、強磁性のα－Ｆｅ相のナノ結晶がＲ酸窒化物相の中に孤立している構造、いわゆる海（Ｒ酸窒化物相）－島（ナノα－Ｆｅ相）構造を有していてもよい。ここで、α－Ｆｅ、ならびに希土類Ｒの酸化物、窒化物、および酸窒化物からなる群から選択される物質をＲ酸窒化物というものとする。α－Ｆｅ含有領域が海（Ｒ酸窒化物相）－島（ナノα－Ｆｅ相）構造を有することで、α－Ｆｅ金属相がそれぞれ、「海」であるＲ酸窒化物マトリックス相中で孤立しており、電子のパーコレーションは起こらず電気的絶縁が保たれる。
また、α－Ｆｅ含有領域中のα－Ｆｅ相が規則的に配列していてもよい。α－Ｆｅ含有領域中のα－Ｆｅ相が規則的に配列している場合、α－Ｆｅ相がナノ結晶の粒子で構成され、かつ、高い密度で規則的に配列することが可能となり、それぞれのα－Ｆｅ相が強磁性結合若しくは静磁気結合し、α－Ｆｅ含有領域を貫いて磁束が通りやすくなることで、磁気的結合もより安定となる傾向がある。 The α-Fe-containing region has a structure in which ferromagnetic α-Fe phase nanocrystals are isolated in the R oxynitride phase, a so-called sea (R oxynitride phase)-island (nano α-Fe phase). It may have a structure. Here, a substance selected from the group consisting of α-Fe and rare earth R oxides, nitrides, and oxynitrides is referred to as R oxynitride. Since the α-Fe-containing region has a sea (R oxynitride phase)-island (nano α-Fe phase) structure, each α-Fe metal phase is in the “sea” R oxynitride matrix phase. Since it is isolated, no electron percolation occurs and electrical insulation is maintained.
Further, the α-Fe phase in the α-Fe containing region may be regularly arranged. When the α-Fe phase in the α-Fe-containing region is regularly arranged, it becomes possible for the α-Fe phase to be composed of nanocrystalline particles and to be arranged regularly with high density, and each The α-Fe phase of the α-Fe phase is ferromagnetically or magnetostatically coupled, and magnetic flux tends to pass through the α-Fe-containing region more easily, thereby making the magnetic bond more stable.
　また、α－Ｆｅ含有領域は、海領域および島領域を含む海－島構造を有し、Ｆｅの原子濃度（％）は島領域の方が海領域よりも高く、希土類ＲおよびＯの原子濃度（％）は島領域の方が海領域よりも低い構造を有していてもよい。島領域におけるＦｅの原子濃度（％）は、海領域におけるＦｅの原子濃度（％）よりも１０ポイント以上高いことが好ましく、２０ポイント以上高いことがより好ましい。海領域における希土類ＲおよびＯの原子濃度（％）は、島領域における希土類ＲおよびＯの原子濃度（％）よりも、それぞれ２ポイント以上高いことが好ましく、５ポイント以上高いことがより好ましい。島領域、海領域中の各元素の原子濃度（％）は、ＳＴＥＭ－ＥＤＸライン分析において各領域中の原子濃度を平均することにより求められる。 In addition, the α-Fe containing region has a sea-island structure including a sea region and an island region, and the atomic concentration (%) of Fe is higher in the island region than in the sea region, and the atomic concentration of rare earths R and O is higher in the island region than in the sea region. (%) may have a lower structure in the island region than in the sea region. The Fe atomic concentration (%) in the island region is preferably 10 points or more higher than the Fe atomic concentration (%) in the sea region, and more preferably 20 points or more higher. The atomic concentration (%) of rare earths R and O in the sea region is preferably 2 points or more higher, and more preferably 5 points or more higher than the atomic concentration (%) of rare earths R and O in the island region. The atomic concentration (%) of each element in the island region and the sea region is determined by averaging the atomic concentration in each region in STEM-EDX line analysis.
　α－Ｆｅ含有希土類－鉄－窒素系磁性粉体は、ＸＲＤ測定した際に以下の特徴を有していても良い。α－Ｆｅ含有希土類－鉄－窒素系磁性粉体は、α－Ｆｅ相とＲ酸窒化物相の格子整合のため、α－Ｆｅ（１１０）面回折ピーク強度の中には、Ｒ酸窒化物分の回折ピーク強度も加算されており、見かけ上、α－Ｆｅ（１１０）面回折ピーク強度が、α－Ｆｅ相とＲ酸窒化物相の格子整合のない場合に期待されるピーク強度よりも強く検出される。配向した結晶相の大きさは、α－Ｆｅ含有領域の膜厚の１～１００％が好ましく、１０～１００％がより好ましい。１％未満であると磁気的連結の効果が小さくなる。配向している領域のα－Ｆｅ含有領域に対する体積分率は大きいほどよく、好ましくは１～１００％、より好ましくは１０～１００％である。１％以上であると磁気的連結のエンハンス効果が無配向のときと比較してより大きくなる場合がある。 The α-Fe-containing rare earth-iron-nitrogen magnetic powder may have the following characteristics when measured by XRD. α-Fe-containing rare earth-iron-nitrogen magnetic powder has a lattice matching between α-Fe phase and R oxynitride phase, so the α-Fe(110) plane diffraction peak intensity contains R oxynitride. The diffraction peak intensity of Strongly detected. The size of the oriented crystal phase is preferably 1 to 100%, more preferably 10 to 100%, of the film thickness of the α-Fe-containing region. When it is less than 1%, the effect of magnetic coupling becomes small. The larger the volume fraction of the oriented region to the α-Fe-containing region is, the better, preferably 1 to 100%, more preferably 10 to 100%. When the amount is 1% or more, the enhancement effect of magnetic coupling may become larger than that without orientation.
　配向した結晶相の有無や、その大きさおよび体積分率は、α－Ｆｅ含有希土類－鉄－窒素系磁性粉体のＳＴＥＭ像の観察や、ＴＥＭ装置に付属のＥＤ（電子線回折）装置などにより測定することができる。例えば、α－Ｆｅ含有希土類－鉄－窒素系磁性粉体の断面ＳＴＥＭ写真中でα－Ｆｅ相とＲ酸窒化物相の双方を含んで一方向に格子縞が存在する領域を「配向している領域」として、画像解析を行う。走査透過型電子顕微鏡（ＳＴＥＭ）を用いて、α－Ｆｅ含有希土類－鉄－窒素系磁性粉体のα－Ｆｅ含有領域を含む領域（α－Ｆｅ含有領域が厚い場合、複数視野に分けてもよい）を５か所撮影し、撮影した領域中の「配向している領域」とそうでない領域とを比較することで、配向した結晶相の大きさや体積分率を確認することができる。また、ＳＴＥＭ－ＥＤ像の電子線回折パターンにより、配向した結晶の有無を確認することができる。 The presence or absence of an oriented crystal phase, its size, and volume fraction can be determined by observing a STEM image of α-Fe-containing rare earth-iron-nitrogen magnetic powder or using an ED (electron diffraction) device attached to a TEM device. It can be measured by For example, in a cross-sectional STEM photograph of an α-Fe-containing rare earth-iron-nitrogen magnetic powder, a region containing both an α-Fe phase and an R oxynitride phase and having lattice fringes in one direction is considered to be ``oriented.'' Image analysis is performed as "area". Using a scanning transmission electron microscope (STEM), the region including the α-Fe-containing region of α-Fe-containing rare earth-iron-nitrogen magnetic powder (if the α-Fe-containing region is thick, it can be divided into multiple fields of view) The size and volume fraction of the oriented crystal phase can be confirmed by photographing five locations of the oriented crystal phase and comparing the "oriented region" and the non-oriented region among the photographed regions. Further, the presence or absence of oriented crystals can be confirmed by the electron beam diffraction pattern of the STEM-ED image.
＜リン化合物被覆部＞
　α－Ｆｅ含有希土類－鉄－窒素系磁性粉体は、さらにリン化合物被覆部を有していることが好ましい。リン化合物被覆部は、α－Ｆｅ含有領域の外側、すなわちα－Ｆｅ含有領域を挟んでコア領域の反対側に存在することが好ましい。 <Phosphorus compound coated part>
The α-Fe-containing rare earth-iron-nitrogen magnetic powder preferably further has a phosphorus compound coating. The phosphorus compound coating portion is preferably present outside the α-Fe-containing region, that is, on the opposite side of the core region across the α-Fe-containing region.
　リン化合物被覆部の厚みは、高周波領域における磁性材料のｔａｎδ及び位相角θや、超高周波領域でのμ”を向上させる観点から、１ｎｍ以上２００ｎｍ以下が好ましく、２ｎｍ以上５０ｎｍ以下がより好ましい。なお、被覆部の厚みは、α－Ｆｅ含有希土類－鉄－窒素系磁性粉体の断面にＴＥＭ、ＳＴＥＭ又はＦＥ－ＳＥＭ観察像においてＥＤＸによるライン分析或いは面分析、さらに十分な測定点数を実施した点分析によって組成分析を行うことにより測定できる。なお、ライン分析などで測定する際、例えば、リン（Ｐ）の原子濃度が１原子％以上として観測される範囲をリン化合物被覆部とみなしてもよい。一例として、リン化合物被覆部がα－Ｆｅ含有希土類－鉄－窒素系磁性粉体の表面を全面被覆（表面被覆率１００％）している構造が挙げられる。この場合、隣り合う磁性粒子は完全に電気的な絶縁された状態にあると考えられる。すなわち、この構造であれば、粒間をまたぐ渦電流による鉄損をリン化合物被覆部により低減する効果があって、高周波領域のｔａｎδや位相角θがより向上し、より高効率の磁場増幅用磁性材料が得られる。また、超高周波領域まで渦電流の影響を低減でき、より高い超高周波吸収特性が保たれた超高周波吸収用磁性材料とすることができる。なお、リン化合物被覆部は完全にα－Ｆｅ含有希土類－鉄－窒素系磁性粉体表面を被覆していなくてもよく、１０％以上の表面被覆率であれば、ある程度の渦電流低減の効果が期待できる。好ましくは５０％以上、より好ましくは８０％以上の表面被覆率が望まれる。１０％以上８０％未満の表面被覆率では、遊離したリン化合物が磁性粉体間に存在している方が好ましい。磁性粉体のリン化合物被覆部による表面被覆率は、粉体の断面を、ＥＤＸが備えられたＴＥＭ、ＳＴＥＭ又はＦＥ－ＳＥＭで観測して見積もることができ、観察されるα－Ｆｅ含有希土類－鉄－窒素系磁性粉体表面の全体周長に対するリンを含む被膜の接触部分の長さの比を「表面被覆率」と定義する。この際、上述の方法で観察される画像の中から２０個から５０個の磁性粉体の断面を測定し、平均した値を表面被覆率とすることが好ましい。 The thickness of the phosphorus compound coating part is preferably 1 nm or more and 200 nm or less, more preferably 2 nm or more and 50 nm or less, from the viewpoint of improving the tan δ and phase angle θ of the magnetic material in the high frequency region and μ'' in the ultra-high frequency region. The thickness of the coating part is determined by line analysis or surface analysis using EDX on a cross section of the α-Fe-containing rare earth-iron-nitrogen magnetic powder in a TEM, STEM, or FE-SEM observation image, and a sufficient number of measurement points. It can be measured by performing compositional analysis by analysis.In addition, when measuring by line analysis etc., for example, the range where the atomic concentration of phosphorus (P) is observed as 1 atomic% or more may be regarded as the phosphorus compound coating area. An example is a structure in which the phosphorus compound coating part completely covers the surface of α-Fe-containing rare earth-iron-nitrogen magnetic powder (surface coverage rate 100%).In this case, adjacent magnetic particles It is considered to be in a completely electrically insulated state.In other words, with this structure, the phosphorus compound coating has the effect of reducing iron loss due to eddy currents that cross between grains, and the tan δ and A magnetic material for magnetic field amplification with higher phase angle θ and higher efficiency can be obtained.In addition, the influence of eddy current can be reduced even in the ultra-high frequency region, and a magnetic material for ultra-high frequency absorption that maintains higher ultra-high frequency absorption characteristics can be obtained. The phosphorus compound coating part does not have to completely cover the surface of the α-Fe-containing rare earth-iron-nitrogen magnetic powder, but as long as the surface coverage is 10% or more, A certain degree of eddy current reduction effect can be expected. A surface coverage of preferably 50% or more, more preferably 80% or more is desired. If the surface coverage is 10% or more and less than 80%, the free phosphorus compound will be absorbed by the magnetic powder. It is preferable that the magnetic powder be present between the particles.The surface coverage rate of the phosphorus compound coating part of the magnetic powder can be estimated by observing the cross section of the powder with a TEM, STEM, or FE-SEM equipped with EDX. The ratio of the length of the contact portion of the phosphorus-containing film to the total circumference of the surface of the α-Fe-containing rare earth-iron-nitrogen magnetic powder that is formed and observed is defined as "surface coverage." At this time, it is preferable to measure the cross sections of 20 to 50 magnetic powders from among the images observed by the above-mentioned method, and take the average value as the surface coverage.
　リン化合物被覆部を構成するリン化合物としては、オルトリン酸、ピロリン酸、ポリリン酸などの無機リン酸、および、それらとＮａ、Ｃａ、Ｐｂ、Ｚｎ、Ｆｅ、Ｒ、アンモニウム、Ｍｏ、Ｗ、Ｖ、Ｃｒ（これらの金属元素、原子団を本開示ではＭ成分といい、単にＭと表記する場合もある）などとのリン酸塩などのリン酸化合物やＲ、Ｆｅ、Ｍ及びＮの中から選択される少なくとも１種とＰ及び／又はリン含有物を含む「リン含有アモルファス化合物」や「リン含有ナノ結晶化合物」などが挙げられる。なかでも、コア領域およびα－Ｆｅ含有領域から構成される粉体の表面被覆を緻密なものとするなどの点で、リン酸塩、「リン含有アモルファス化合物」や「リン含有ナノ結晶化合物」が好ましい。上記「リン含有ナノ結晶含有物」は、希土類リン酸塩であるか、或いは、リン酸鉄及びリン酸Ｍの中から少なくとも１種と希土類リン酸塩を含む共晶や混晶の状態にあってもいい。「リン含有ナノ結晶化合物」を含むとさらに熱安定性が良くなるので、リン処理後のボンド磁性材料作製時に高熱が加わる、混練工程、熱硬化工程を経ても、磁性粉体の高周波特性が劣化しにくい傾向があり、さらに最終成形体の高い熱安定性や優れた効率にも寄与する。ここで、ナノ結晶とは、１ｎｍ以上１μｍ未満の微細結晶のことをいい、１ｎｍ未満の微細結晶を含むリン化合物はアモルファス化合物の範疇にあるとする。リン化合物被覆部の結晶性、リン化合物被覆部中の微細結晶の径については、ＴＥＭ法による格子像観察、ＴＥＭ装置に付属のＥＤ（電子線回折）装置による解析で確認することができる。 The phosphorus compounds constituting the phosphorus compound coating include inorganic phosphoric acids such as orthophosphoric acid, pyrophosphoric acid, and polyphosphoric acid, and inorganic phosphoric acids such as Na, Ca, Pb, Zn, Fe, R, ammonium, Mo, W, V, Selected from phosphoric acid compounds such as phosphates with Cr (these metal elements and atomic groups are referred to as M components in this disclosure, and may be simply written as M), R, Fe, M, and N. Examples include "phosphorus-containing amorphous compounds" and "phosphorus-containing nanocrystalline compounds" that contain at least one type of P and/or phosphorus-containing substances. Among these, phosphates, ``phosphorus-containing amorphous compounds'' and ``phosphorus-containing nanocrystalline compounds'' are particularly effective in making the surface coating of the powder consisting of the core region and α-Fe-containing region dense. preferable. The above-mentioned "phosphorus-containing nanocrystal-containing material" is a rare earth phosphate, or is in a eutectic or mixed crystal state containing at least one of iron phosphate and phosphate M and a rare earth phosphate. It's okay. Containing a "phosphorus-containing nanocrystalline compound" further improves thermal stability, so even if high heat is applied during the production of bonded magnetic materials after phosphorus treatment, such as kneading and thermosetting processes, the high-frequency properties of the magnetic powder will deteriorate. It also contributes to the high thermal stability and excellent efficiency of the final molded product. Here, nanocrystals refer to fine crystals of 1 nm or more and less than 1 μm, and phosphorus compounds containing fine crystals of less than 1 nm are in the category of amorphous compounds. The crystallinity of the phosphorus compound coated portion and the diameter of fine crystals in the phosphorus compound coated portion can be confirmed by lattice image observation using the TEM method and analysis using an ED (electron diffraction) device attached to the TEM device.
　α－Ｆｅ含有希土類－鉄－窒素系磁性粉体中のリン化合物の含有量は、０．５質量％以上４．５質量％以下が好ましく、０．５５質量％以上２．５質量％以下がより好ましく、０．７５質量％以上２質量％以下が最も好ましい。４．５質量％以下であると、希土類－鉄－窒素系磁性粉体の凝集を低減できることがあり、比透磁率の低下を抑制すると同時に、高周波領域でのｔａｎδや位相角θの悪化を低減できる傾向がある。０．５質量％以上であることで、リン化合物被覆部の電気的絶縁性がより向上することで、同様に比透磁率の低下を抑制し、高周波領域でのｔａｎδや位相角θが悪化を低減できる傾向がある。 The content of the phosphorus compound in the α-Fe-containing rare earth-iron-nitrogen magnetic powder is preferably 0.5% by mass or more and 4.5% by mass or less, and 0.55% by mass or more and 2.5% by mass or less. More preferably, 0.75% by mass or more and 2% by mass or less is most preferred. If it is 4.5% by mass or less, it may be possible to reduce the aggregation of rare earth-iron-nitrogen magnetic powder, suppressing the decrease in relative magnetic permeability, and at the same time reducing the deterioration of tan δ and phase angle θ in the high frequency region. There is a tendency to do so. When the content is 0.5% by mass or more, the electrical insulation of the phosphorus compound coating is further improved, which also suppresses a decrease in relative magnetic permeability and prevents deterioration of tan δ and phase angle θ in the high frequency region. There is a tendency that it can be reduced.
　また、α－Ｆｅ含有希土類－鉄－窒素系磁性粉体中におけるリン（Ｐ）元素の含有量は０．０２質量％以上が好ましく、０．０５質量％以上がより好ましく、０．１５質量％以上がさらに好ましい。α－Ｆｅ含有希土類－鉄－窒素系磁性粉体中のリンの含有量は４質量％以下が好ましく、２質量％以下がより好ましく、１質量％以下がさらに好ましい。 Further, the content of the phosphorus (P) element in the α-Fe-containing rare earth-iron-nitrogen magnetic powder is preferably 0.02% by mass or more, more preferably 0.05% by mass or more, and 0.15% by mass. The above is more preferable. The phosphorus content in the α-Fe-containing rare earth-iron-nitrogen magnetic powder is preferably 4% by mass or less, more preferably 2% by mass or less, and even more preferably 1% by mass or less.
　リン化合物は、渦電流による効率の低下、すなわちｔａｎδや位相角θの悪化をもたらさないという点で、コア領域およびα－Ｆｅ含有領域から構成される粉体の少なくとも一部の表面を被覆していることが好ましい。磁性粉体において、１０％以上の表面被覆率であれば、ある程度の渦電流低減の効果があるが、好ましくは５０％以上、さらに好ましくは８０％以上の表面被覆率が望まれる。１０％以上の表面被覆率であると、粒間に生ずる渦電流を抑制し、ｔａｎδや位相角θの悪化を低減できる傾向がある。リン化合物被覆部により、１００％の被覆率を有するα－Ｆｅ含有希土類－鉄－窒素系磁性粉体は、ｔａｎδや位相角θが極めて悪化し、磁性粉体の組成、結晶構造及び粉体粒径などによるが、２ＭＨｚで０．０１以下のｔａｎδ及び高いθを実現できる。 The phosphorus compound coats at least a portion of the surface of the powder consisting of the core region and the α-Fe-containing region in that it does not reduce efficiency due to eddy currents, that is, it does not cause deterioration of tan δ or phase angle θ. Preferably. In magnetic powder, a surface coverage of 10% or more is effective in reducing eddy current to some extent, but a surface coverage of 50% or more, more preferably 80% or more is desired. A surface coverage of 10% or more tends to suppress eddy currents generated between grains and reduce deterioration of tan δ and phase angle θ. Due to the phosphorus compound coating, the α-Fe-containing rare earth-iron-nitrogen magnetic powder with a coverage rate of 100% has extremely deteriorated tan δ and phase angle θ, and the composition, crystal structure, and powder grains of the magnetic powder deteriorate. Although it depends on the diameter, tan δ of 0.01 or less and high θ can be achieved at 2 MHz.
　リン化合物は、渦電流による比透磁率の低下、特にμ”の低下、すなわち超高周波吸収特性の悪化をもたらさないという点でも、コア領域およびα－Ｆｅ含有領域から構成される粉体の少なくとも一部の表面を被覆していることが好ましい。１０％以上の表面被覆率であれば、ある程度の渦電流低減の効果があるが、好ましくは５０％以上、さらに好ましくは８０％以上の表面被覆率が望まれる。１０％より小さい表面被覆率であると、十分に粒間に生ずる渦電流を阻止できず、表皮効果によりμ”が低下する傾向がある。リン化合物被覆部により、１００％の被覆率を有するα－Ｆｅ含有希土類－鉄－窒素系磁性粉体は、渦電流による比透磁率の低下が極めて小さくなり、磁性粉体の組成、結晶構造及び粉体粒径などによるが、１ＧＨｚで１以上のμ”を実現できる。 The phosphorus compound is effective in at least one part of the powder consisting of the core region and the α-Fe-containing region, in that it does not cause a decrease in relative magnetic permeability due to eddy currents, especially a decrease in μ'', that is, a deterioration in ultra-high frequency absorption characteristics. It is preferable that the surface of the part is covered.A surface coverage of 10% or more has the effect of reducing eddy current to some extent, but preferably a surface coverage of 50% or more, more preferably 80% or more. If the surface coverage is less than 10%, eddy currents generated between grains cannot be sufficiently prevented, and μ'' tends to decrease due to the skin effect. Due to the phosphorus compound coating, α-Fe-containing rare earth-iron-nitrogen magnetic powder with a coverage rate of 100% has an extremely small decrease in relative permeability due to eddy current, and the composition, crystal structure and Depending on the powder particle size, etc., it is possible to achieve μ'' of 1 or more at 1 GHz.
　α－Ｆｅ含有希土類－鉄－窒素系磁性粉体の表面に存在するリン化合物被覆部は、希土類（Ｒ）原子濃度が、母材である希土類－鉄－窒素系磁性粉体（コア領域）中のＲ原子濃度より高い領域（Ｒ高濃度領域）を有していてもよい。Ｒ高濃度領域中のＲ原子濃度は、コア領域中のＲ原子濃度の１．０５倍以上とすることができ、１．１倍以上が好ましく、１．２倍以上がより好ましく、１．５倍以上がさらに好ましい。また、Ｒ高濃度領域中のＲ原子濃度は、例えばコア領域中のＲ原子濃度の４倍以下とすることができる。ここで、Ｒ高濃度領域は、α－Ｆｅ含有希土類－鉄－窒素系磁性粉体のＳＴＥＭ－ＥＤＸライン分析においてＰ（リン）の最大ピークを示す層を包含する領域である。Ｒ高濃度領域の厚みは例えば１ｎｍ以上とすることができ、３ｎｍ以上１５０ｎｍ以下が好ましく、５ｎｍ以上１００ｎｍ以下がより好ましい。Ｒ高濃度領域中のＲ原子濃度がコア領域中のＲ原子濃度に対して、上述の範囲にあることで、電気抵抗率が高くなり、比透磁率を高くできる傾向がある。Ｒ高濃度領域中の各元素の原子濃度（原子％）は、ＳＴＥＭ－ＥＤＸライン分析におけるリン化合物被覆部中の原子濃度を平均することにより求められる。希土類元素としては例えばＮｄであってよく、その場合、Ｎｄ高濃度領域として、Ｎｄ原子濃度を基準として評価することができる。 The phosphorus compound coating portion existing on the surface of the α-Fe-containing rare earth-iron-nitrogen magnetic powder has a rare earth (R) atomic concentration that is higher than that of the rare earth-iron-nitrogen magnetic powder (core region), which is the base material. may have a region (R high concentration region) where the R atom concentration is higher than the R atom concentration. The R atom concentration in the R high concentration region can be 1.05 times or more than the R atom concentration in the core region, preferably 1.1 times or more, more preferably 1.2 times or more, and 1.5 times or more. More preferably, it is twice or more. Further, the R atom concentration in the R high concentration region can be, for example, four times or less than the R atom concentration in the core region. Here, the R high concentration region is a region including a layer showing the maximum peak of P (phosphorus) in STEM-EDX line analysis of α-Fe-containing rare earth-iron-nitrogen magnetic powder. The thickness of the R high concentration region can be, for example, 1 nm or more, preferably 3 nm or more and 150 nm or less, and more preferably 5 nm or more and 100 nm or less. When the R atom concentration in the R high concentration region is within the above-mentioned range with respect to the R atom concentration in the core region, the electric resistivity tends to be high and the relative magnetic permeability can be increased. The atomic concentration (atomic %) of each element in the R high concentration region is determined by averaging the atomic concentration in the phosphorus compound coating part in STEM-EDX line analysis. The rare earth element may be, for example, Nd, and in that case, the Nd atomic concentration can be evaluated as a high Nd concentration region.
　Ｒ高濃度領域中でのＲ原子濃度は、Ｒ高濃度領域中のＦｅ原子濃度の０．３倍以上であってよく、１倍以上が好ましい。Ｒ高濃度領域中のＲ原子濃度は、Ｒ高濃度領域中のＦｅ原子濃度の２０倍以下が好ましい。Ｒ高濃度領域中のＲ原子濃度とＦｅ原子濃度の関係が上述の範囲にあることで、コア領域近傍のＦｅ原子濃度が低くなり、耐水性がより向上する傾向がある。 The R atom concentration in the R high concentration region may be 0.3 times or more, preferably 1 times or more, the Fe atom concentration in the R high concentration region. The R atom concentration in the R high concentration region is preferably 20 times or less than the Fe atom concentration in the R high concentration region. When the relationship between the R atom concentration and the Fe atom concentration in the R high concentration region is within the above-mentioned range, the Fe atom concentration near the core region tends to be lower and water resistance to be further improved.
　Ｒ高濃度領域中のＲとＦｅの原子濃度比Ｒ／Ｆｅが、０．３以上であってよく、０．５以上が好ましく、１以上がより好ましい。Ｒ高濃度領域中のＲ／Ｆｅの上限は、１００以下であってよく、１０以下であってもよい。また、Ｒ高濃度領域中のＲ／Ｆｅはコア領域中のＲ／Ｆｅより高い値を有していてもよい。Ｒ高濃度領域中のＲ／Ｆｅはコア領域中のＲ／Ｆｅの１倍以上とすることができ、１．５倍以上が好ましく、２倍以上がより好ましく、５倍以上がさらに好ましい。Ｒ高濃度領域中のＲ／Ｆｅが上述の範囲にあることで、コア領域近傍のＦｅ原子濃度が低くなり、耐水性がより向上する傾向がある。 The atomic concentration ratio R/Fe of R and Fe in the R high concentration region may be 0.3 or more, preferably 0.5 or more, and more preferably 1 or more. The upper limit of R/Fe in the R high concentration region may be 100 or less, or may be 10 or less. Further, R/Fe in the R high concentration region may have a higher value than R/Fe in the core region. R/Fe in the R high concentration region can be 1 times or more the R/Fe in the core region, preferably 1.5 times or more, more preferably 2 times or more, and even more preferably 5 times or more. When R/Fe in the R high concentration region is within the above-mentioned range, the Fe atom concentration near the core region is lowered, and water resistance tends to be further improved.
　α－Ｆｅ含有希土類－鉄－窒素系磁性粉体は、さらにＭｏ高濃度層を有していてもよい。Ｍｏ高濃度層では、リン化合物被覆部を形成する際に使用するＭｏが、酸化鉄層、α－Ｆｅ含有領域よりも高濃度で存在する。Ｍｏ高濃度層はα－Ｆｅ含有領域の外側に存在することが好ましい。場合によっては、Ｍｏ高濃度層を有することにより、被膜層の強度を上げて耐食性を改善する効果がある。 The α-Fe-containing rare earth-iron-nitrogen magnetic powder may further have a Mo high concentration layer. In the Mo high concentration layer, Mo used when forming the phosphorus compound coating is present at a higher concentration than in the iron oxide layer and the α-Fe containing region. The Mo high concentration layer is preferably present outside the α-Fe containing region. In some cases, having a Mo high concentration layer has the effect of increasing the strength of the coating layer and improving corrosion resistance.
　α－Ｆｅ含有希土類－鉄－窒素系磁性粉体が、Ｍｏ高濃度層を含む場合、Ｍｏ高濃度層の厚みは、α－Ｆｅ含有希土類－鉄－窒素系磁性粉体の平均粒径の０．０１％以上１０％以下であることが好ましく、０．０２％以上１％以下であることがより好ましい。また、Ｍｏ高濃度層の厚みは１ｎｍ以上１μｍ以下であることが好ましく、２ｎｍ以上１００ｎｍ以下であることがより好ましい。 When the α-Fe-containing rare earth-iron-nitrogen magnetic powder includes a Mo high concentration layer, the thickness of the Mo high-concentration layer is 0 It is preferably .01% or more and 10% or less, more preferably 0.02% or more and 1% or less. Further, the thickness of the Mo high concentration layer is preferably 1 nm or more and 1 μm or less, and more preferably 2 nm or more and 100 nm or less.
　α－Ｆｅ含有希土類－鉄－窒素系磁性粉体は、さらに酸化鉄層を有していてもよい。酸化鉄層は、Ｆｅ２Ｏ３を含む酸化鉄を主成分とする。酸化鉄層はα－Ｆｅ含有領域の外側に存在することが好ましく、リン化合物被覆部の外側に存在することがより好ましく、Ｍｏ高濃度層の外側に存在することがさらに好ましい。酸化鉄層を有することにより、α－Ｆｅ含有領域の熱力学的な安定性をもたらしたり、電気的絶縁を高めたりする効果がある。 The α-Fe-containing rare earth-iron-nitrogen magnetic powder may further have an iron oxide layer. The iron oxide layer has iron oxide containing Fe 2 O 3 as a main component. The iron oxide layer is preferably present outside the α-Fe-containing region, more preferably outside the phosphorus compound coating, and even more preferably outside the Mo high concentration layer. Having the iron oxide layer has the effect of providing thermodynamic stability to the α-Fe-containing region and increasing electrical insulation.
　α－Ｆｅ含有希土類－鉄－窒素系磁性粉体が、酸化鉄層を有する場合、酸化鉄層の厚みは、α－Ｆｅ含有希土類－鉄－窒素系磁性粉体の平均粒径の０％より大きく２０％以下であることが好ましく、０．００１％以上５％以下であることがより好ましい。２０％以下とすることでμ’の低下を抑制できる傾向がある。また、酸化鉄層の厚みは０ｎｍより大きく１μｍ以下であることが好ましく、１ｎｍ以上１００ｎｍ以下であることがより好ましい。酸化鉄層の厚みを１μｍ以下とすることでμ’の低下を抑制できる傾向がある。 When the α-Fe-containing rare earth-iron-nitrogen magnetic powder has an iron oxide layer, the thickness of the iron oxide layer is less than 0% of the average particle size of the α-Fe-containing rare earth-iron-nitrogen magnetic powder. It is preferably 20% or less, and more preferably 0.001% or more and 5% or less. There is a tendency that a decrease in μ' can be suppressed by setting it to 20% or less. Further, the thickness of the iron oxide layer is preferably greater than 0 nm and less than or equal to 1 μm, and more preferably greater than or equal to 1 nm and less than or equal to 100 nm. There is a tendency that a decrease in μ' can be suppressed by setting the thickness of the iron oxide layer to 1 μm or less.
＜磁性粉体の粒径＞
　α－Ｆｅ含有希土類－鉄－窒素系磁性粉体の平均粒径は、０．１μｍ以上１００μｍ以下が好ましい。磁場増幅用磁性材料としては、１μｍ以上１００μｍ以下が好ましい。超高周波吸収用磁性材料としては、０．１μｍ以上１０μｍ以下が好ましい。より好ましい粒径の範囲は、後述する磁場増幅用磁性材料としては、３μｍ以上１００μｍ以下であり、超高周波吸収用磁性材料としては、０．１μｍ以上３μｍ以下である。１μｍ未満では、成形体中の磁性粉体の充填量が小さくなるため高周波領域における比透磁率の実数項や超高周波領域での比透磁率の虚数項が低下するおそれがある。０．１μｍ以下になるとさらに比表面積が大きくなるために、高周波領域における比透磁率の実数項や超高周波領域での比透磁率の虚数項の高い磁性体部分の体積分率が小さくなる場合がある。この結果として磁性材料としての特性が極端に低くなる傾向がある。１０μｍを超えると、成形体のμ”が低下する傾向があり、さらに１００μｍを超えるとその傾向は顕著となる。ここで、平均粒径は、レーザー回折式粒度分布測定装置を用いて乾式条件で測定したメジアン径のことである。すなわち、本開示の磁性粉体の平均粒径はＤ５０で表し、Ｄ５０とは、α－Ｆｅ含有希土類－鉄－窒素系磁性粉体の体積基準による粒度分布の積算値が５０％に相当する粒径である。 <Particle size of magnetic powder>
The average particle size of the α-Fe-containing rare earth-iron-nitrogen magnetic powder is preferably 0.1 μm or more and 100 μm or less. The magnetic material for magnetic field amplification preferably has a thickness of 1 μm or more and 100 μm or less. The magnetic material for ultra-high frequency absorption preferably has a thickness of 0.1 μm or more and 10 μm or less. A more preferable particle size range is 3 μm or more and 100 μm or less for a magnetic material for magnetic field amplification, which will be described later, and 0.1 μm or more and 3 μm or less for a magnetic material for ultra-high frequency absorption. If it is less than 1 μm, the amount of magnetic powder packed in the compact becomes small, so there is a risk that the real term of relative magnetic permeability in the high frequency range and the imaginary term of the relative magnetic permeability in the ultrahigh frequency range decrease. When it becomes 0.1 μm or less, the specific surface area becomes even larger, so the volume fraction of the magnetic material portion with a high real term of relative magnetic permeability in the high frequency region and a high imaginary term of the relative magnetic permeability in the ultrahigh frequency region may become small. be. As a result, the properties as a magnetic material tend to be extremely poor. When the particle size exceeds 10 μm, the μ” of the molded product tends to decrease, and when the particle size exceeds 100 μm, this tendency becomes more pronounced. It refers to the measured median diameter.In other words, the average particle diameter of the magnetic powder of the present disclosure is expressed as D50, and D50 is the particle size distribution on a volume basis of the α-Fe-containing rare earth-iron-nitrogen magnetic powder. This is the particle size at which the integrated value corresponds to 50%.
　Ｆｅ含有希土類－鉄－窒素系磁性粉体のコア領域の粒径が大きくなると、表皮効果により低い周波数から渦電流が粒内に生じ始めるので、粒径が大きいほど低周波領域から比透磁率の実数項の低下が始まる。従って、磁性粉体の粒径を小さくすることによって、磁場増幅特性や超高周波吸収特性が高周波まで高く保たれる傾向がある。例えば、Ｎｄ２Ｆｅ１７Ｎ３においては、磁性粉体の粒径ｒ（μｍ）と比透磁率の実数項が低下し始める周波数ｆ０（Ｈｚ）との関係は、ｒが０．１μｍであればｆ０＝１ＴＨｚ、３μｍであればｆ０＝１ＧＨｚ、１００μｍであればｆ０＝１ＭＨｚと推測される。従って、粒径の上限値がこの付近となるＦｅ含有希土類－鉄－窒素系磁性粉体のコア領域とすれば、本開示の磁場増幅用磁性材料として好ましい。一方、粒径が小さくなるに従い、成形体中の磁性粉体の充填量が小さくなる上、比表面積が大きくなることから、例えば厚みが１０ｎｍのリン化合物被覆部を有する場合に、粉体の粒径が０．１μｍなら、比透磁率が５０％程度低下するに過ぎなくても、粒径が０．０５μｍとなれば、比透磁率は約６％となってしまうので、本開示のＦｅ含有希土類－鉄－窒素系磁性粉体のコア領域の下限値は周波数に関係なく、０．１μｍ辺りになる。以上のトレードオフがあるために、磁性材料の目的の周波数帯域により適した粒径範囲とすることが好ましい。 When the particle size of the core region of the Fe-containing rare earth-iron-nitrogen magnetic powder increases, eddy currents begin to occur within the grain from low frequencies due to the skin effect. The real term begins to decline. Therefore, by reducing the particle size of the magnetic powder, magnetic field amplification characteristics and ultrahigh frequency absorption characteristics tend to be maintained high up to high frequencies. For example, in Nd 2 Fe 17 N 3 , the relationship between the particle size r (μm) of the magnetic powder and the frequency f 0 (Hz) at which the real term of relative magnetic permeability starts to decrease is as follows even when r is 0.1 μm. It is estimated that f 0 =1 THz if it is 3 μm, f 0 =1 GHz if it is 100 μm, and f 0 =1 MHz if it is 100 μm. Therefore, a core region of Fe-containing rare earth-iron-nitrogen magnetic powder having an upper limit of particle size around this range is preferable as the magnetic material for magnetic field amplification of the present disclosure. On the other hand, as the particle size becomes smaller, the amount of magnetic powder packed in the compact becomes smaller and the specific surface area becomes larger. If the diameter is 0.1 μm, the relative magnetic permeability will only decrease by about 50%, but if the particle size is 0.05 μm, the relative magnetic permeability will be about 6%. The lower limit of the core region of rare earth-iron-nitrogen magnetic powder is around 0.1 μm, regardless of frequency. Because of the above trade-off, it is preferable to set the particle size range to be more suitable for the intended frequency band of the magnetic material.
　α－Ｆｅ含有希土類－鉄－窒素系磁性粉体は、１０ＭＨｚでの比透磁率の実数項（μ’）が６以上であることが好ましく、１０以上であることがより好ましい。１０ＭＨｚでの比透磁率の実数項が６以上であるときに、トランスコア用途として好ましく用いられる。α－Ｆｅ含有希土類－鉄－窒素系磁性粉体の比透磁率は、以下のようにして測定できる。樹脂と磁性粉体の質量割合が３：９７となるように、α－Ｆｅ含有希土類－鉄－窒素系磁性粉体をエポキシ樹脂と混合し、厚みが１ｍｍである評価用磁性材料を作製する。作製した評価用磁性材料をインピーダンスアナライザ（ＨＰ４２９１Ｂ、ヒューレットパッカード社製）により、評価することで測定することができる。以下、１ＭＨｚ以上１ＧＨｚ未満におけるμ’、μ”、δおよびθの評価については同様の評価用磁性材料を作製することで評価できる。 The α-Fe-containing rare earth-iron-nitrogen magnetic powder preferably has a real number term (μ') of relative magnetic permeability at 10 MHz of 6 or more, more preferably 10 or more. When the real number term of relative magnetic permeability at 10 MHz is 6 or more, it is preferably used for transformer core applications. The relative magnetic permeability of α-Fe-containing rare earth-iron-nitrogen magnetic powder can be measured as follows. A magnetic material for evaluation with a thickness of 1 mm is prepared by mixing α-Fe-containing rare earth-iron-nitrogen magnetic powder with an epoxy resin so that the mass ratio of resin and magnetic powder is 3:97. It can be measured by evaluating the produced magnetic material for evaluation using an impedance analyzer (HP4291B, manufactured by Hewlett-Packard). Hereinafter, evaluation of μ', μ'', δ, and θ at frequencies of 1 MHz or more and less than 1 GHz can be performed by producing similar magnetic materials for evaluation.
　α－Ｆｅ含有希土類－鉄－窒素系磁性粉体は、１００ＭＨｚでの位相角をθ１とし、２ＭＨｚでの位相角をθ２としたとき、θ１／θ２が０．８以上であることが好ましく、０．９以上であることがより好ましい。θ１／θ２が０．８以上であって１に近いほど、高周波でもエネルギー効率の低下を低減できる。なお、位相角θはμ’（複素比透磁率の実数項）とμ”（複素比透磁率の虚数項）を複素平面上に表したときの位相角であり、上述で定義した、ｔａｎδ中のδの余角である位相角θのことである。 The α-Fe-containing rare earth-iron-nitrogen magnetic powder has a ratio of θ 1 /θ 2 of 0.8 or more, where the phase angle at 100 MHz is θ 1 and the phase angle at 2 MHz is θ 2 . is preferable, and more preferably 0.9 or more. The closer θ 1 /θ 2 is to 0.8 and 1, the more the decrease in energy efficiency can be reduced even at high frequencies. Note that the phase angle θ is the phase angle when μ' (real number term of complex relative magnetic permeability) and μ'' (imaginary number term of complex relative magnetic permeability) are expressed on the complex plane, and is the phase angle in tanδ defined above. is the phase angle θ which is the complementary angle of δ.
　α－Ｆｅ含有希土類－鉄－窒素系磁性粉体は、１３ＭＨｚでの位相角θが８５°以上（ｔａｎδが０．０８７５以下）であることが好ましく、８８°以上（ｔａｎδが０．０３４９以下）であることがより好ましい。１３ＭＨｚでの位相角θが８５°以上である時にはＲＦＩＤのアンテナ材料として好適に用いられる。 The α-Fe-containing rare earth-iron-nitrogen magnetic powder preferably has a phase angle θ of 85° or more (tan δ of 0.0875 or less) at 13 MHz, and preferably 88° or more (tan δ of 0.0349 or less). It is more preferable that When the phase angle θ at 13 MHz is 85° or more, it is suitably used as an RFID antenna material.
　なお、本実施形態のＦｅ含有希土類－鉄－窒素系磁性粉体のコア領域の磁気異方性は、磁気モーメントがｃ軸方向より、ｃ面方向を向きやすい性質を有する面内結晶磁気異方性を示す。本実施形態の磁性粉体がこの特性を有することが、高周波領域で高い比透磁率の実数項μ’を維持し、さらに超高周波領域で高い比透磁率の虚数項μ”を発現するために極めて重要である。本実施形態の磁性粉体における、負の結晶磁気異方性エネルギーの絶対値は非常に大きく、さらにこの面内結晶磁気異方性を有した磁性粉体が無配向で含有されるので、その自然共鳴周波数は１ＧＨｚ以上１ＴＨｚ以下の範囲内で広く分布する。従って、１ＧＨｚ未満では自然共鳴によるμ”の増加とμ’の低下が生じることなく、１ＧＨｚ以上１ＴＨｚ以下の領域では広帯域で自然共鳴による高いμ”が発現する。特に本実施形態の磁性粉体では、磁性粉体に含まれるリン化合物やα－Ｆｅ含有領域により強磁性粉体表面が被覆されていたり、磁性粉体間にリン化合物や酸化鉄層が存在したりすることにより、粒間の渦電流の発生を抑止できる。さらに磁性粉体を特定の平均粒径とした際には、粒内の渦電流の発生も抑制されるので、磁性粉体本来の高周波特性が、渦電流による劣化が小さくなり、１ＭＨｚ～１ＴＨｚの領域でより向上する傾向がある。このような広い周波数帯域を一気に網羅した材料設計思想により作り上げられた、「磁場増幅用磁性材料」は知られていない。また、同様の設計思想で、“超広周波数帯域”でシームレスに機能する「超高周波吸収材料」も知られていない。 The magnetic anisotropy of the core region of the Fe-containing rare earth-iron-nitrogen magnetic powder of this embodiment is an in-plane magnetocrystalline anisotropy in which the magnetic moment is more likely to be oriented in the c-plane direction than in the c-axis direction. Show your gender. The fact that the magnetic powder of the present embodiment has this property allows it to maintain the real number term μ' of high relative magnetic permeability in the high frequency region, and further express the imaginary number term μ' of high relative magnetic permeability in the ultra-high frequency region. This is extremely important.The absolute value of the negative magnetocrystalline anisotropy energy in the magnetic powder of this embodiment is very large, and furthermore, the magnetic powder with this in-plane magnetocrystalline anisotropy is contained without orientation. Therefore, its natural resonance frequency is widely distributed within the range of 1 GHz to 1 THz. Therefore, below 1 GHz, there is no increase in μ'' and decrease in μ' due to natural resonance, but in the range of 1 GHz to 1 THz, A high μ'' due to natural resonance occurs in a wide band.In particular, in the magnetic powder of this embodiment, the surface of the ferromagnetic powder is coated with a phosphorus compound or an α-Fe-containing region contained in the magnetic powder, or The presence of phosphorus compounds or iron oxide layers between particles can suppress the generation of eddy currents between grains.Furthermore, when the magnetic powder has a specific average particle size, the eddy currents within the grains can be suppressed. As the generation is also suppressed, the inherent high-frequency characteristics of magnetic powder are less likely to deteriorate due to eddy currents, and tend to be further improved in the 1MHz to 1THz region.A material design concept that covers such a wide frequency band at once The ``magnetic material for magnetic field amplification'' created by the authors is not known. Furthermore, there is no known ``ultra-high frequency absorbing material'' that uses a similar design concept and functions seamlessly in an ``ultra-wide frequency band.''
＜＜磁場増幅用磁性材料＞＞
　本実施形態の磁場増幅用磁性材料は、α－Ｆｅ含有希土類－鉄－窒素系磁性粉体を含むことを特徴とする。α－Ｆｅ含有希土類－鉄－窒素系磁性粉体を含むことにより、磁場増幅用として１ＭＨｚ以上１ＧＨｚ未満の領域でμ’が２以上の高比透磁率を有するとともに、１ＭＨｚ以上１ＧＨｚ未満の領域で位相角θがより高くなるような、優れた効率を併せ持っていてもよい。 <<Magnetic materials for magnetic field amplification>>
The magnetic material for magnetic field amplification of this embodiment is characterized by containing α-Fe-containing rare earth-iron-nitrogen magnetic powder. By containing α-Fe-containing rare earth-iron-nitrogen magnetic powder, it has a high relative permeability with μ' of 2 or more in the range of 1 MHz or more and less than 1 GHz for magnetic field amplification, and has a high relative permeability of μ' of 2 or more in the range of 1 MHz or more and less than 1 GHz. It may also have excellent efficiency such that the phase angle θ becomes higher.
　α－Ｆｅ含有希土類－鉄－窒素系磁性粉体は１μｍ以上１００μｍ以下の粒径が好ましい。その理由は上述したとおりであり、１００μｍより大きい粉体を１ＭＨｚ以上の磁場増幅用磁性材料として使用すると、表皮効果により、比透磁率が低下する傾向にあるからである。さらに、７μｍ以上の粉体を磁場増幅用磁性材料として活用する際には、体積分率を大きくするために大抵０．５ＧＰａ以上の大きな圧力をかけるので、粉体同士が接して大きな渦電流損失が生じ、比透磁率の実数項が大きく低下する。従って、フェライトや遷移金属の酸化物のように固くなく、樹脂のように柔らかすぎないリン化合物のような微細で適度に柔らかい物質がα－Ｆｅ含有希土類－鉄－窒素系磁性粉体を覆うことや、粒間に介在することが好ましく、それにより磁性粉体の本来有する比透磁率などの特性の悪化を抑制できる。 The α-Fe-containing rare earth-iron-nitrogen magnetic powder preferably has a particle size of 1 μm or more and 100 μm or less. The reason for this is as described above, and when powder larger than 100 μm is used as a magnetic material for amplifying a magnetic field of 1 MHz or more, the relative magnetic permeability tends to decrease due to the skin effect. Furthermore, when using powder of 7 μm or more as a magnetic material for magnetic field amplification, a large pressure of 0.5 GPa or more is usually applied to increase the volume fraction, so the powder comes into contact with each other and causes a large eddy current loss. occurs, and the real number term of relative magnetic permeability decreases significantly. Therefore, it is necessary to cover the α-Fe-containing rare earth-iron-nitrogen magnetic powder with a fine and moderately soft substance such as a phosphorus compound that is not hard like ferrite or transition metal oxides and not too soft like resin. It is preferable for the magnetic powder to be present between the grains, thereby suppressing the deterioration of the properties inherent in the magnetic powder, such as the relative magnetic permeability.
　磁場増幅用磁性材料は、１ＭＨｚ以上１ＧＨｚ未満の周波数で好適に使用されるが、１ＧＨｚ以上では、超高周波吸収用磁性材料としても使用される。そのため、α－Ｆｅ含有希土類－鉄－窒素系磁性粉体の組成や粒度分布などによっては、０．５ＧＨｚ以上１ＧＨｚ未満の周波数領域で比透磁率の虚数項が大きくなり始める場合がある。本実施形態の磁場増幅用磁性材料は、１ＭＨｚ以上０．５ＧＨｚ未満の領域で使用してもよく、１ＭＨｚ以上０．１ＧＨｚ未満で使用することが好ましい。上述の範囲で磁場増幅用磁性材料として使用すると、ジェットミルなどの微粉砕装置を採用せず３μｍ以上１００μｍ以下の粉体を使用し、スループットが落ちる磁場配向なども行う必要がなくなるため、コストと特性のバランスの観点で好ましい。 The magnetic material for magnetic field amplification is suitably used at a frequency of 1 MHz or more and less than 1 GHz, but at 1 GHz or more, it is also used as a magnetic material for ultra-high frequency absorption. Therefore, depending on the composition, particle size distribution, etc. of the α-Fe-containing rare earth-iron-nitrogen magnetic powder, the imaginary term of the relative magnetic permeability may begin to increase in the frequency range from 0.5 GHz to less than 1 GHz. The magnetic material for magnetic field amplification of this embodiment may be used in a range of 1 MHz or more and less than 0.5 GHz, and preferably used in a range of 1 MHz or more and less than 0.1 GHz. When used as a magnetic material for magnetic field amplification within the above-mentioned range, there is no need to use a pulverizer such as a jet mill, use powder with a size of 3 μm or more and 100 μm or less, and eliminate the need for magnetic field orientation, which reduces throughput, resulting in lower costs. Preferable from the viewpoint of balance of characteristics.
　磁場増幅用磁性材料のより具体的な用途としては、無線給電のコイル、ＲＦＩＤ（Ｒａｄｉｏ　Ｆｒｅｑｕｅｎｃｙ　Ｉｄｅｎｔｉｆｉｃａｔｉｏｎ）タグ用磁場増幅材、２０ＭＨｚを超える高周波用回路のトランス、インダクタ及びリアクトルなどが挙げられる。たとえば、薄いシート状として、アンテナや受発信機の裏面に張り付け、磁場増幅特性によりシート内に磁束を集中させたり、円柱状や直方体状のコイルの内部に挿入したりする、或いはドーナツ状やヨーク付きの磁芯に導線を巻き付けてコイルの比透磁率の実数項を向上させ、磁場増幅用磁性材料として使用する。 More specific applications of magnetic materials for magnetic field amplification include wireless power supply coils, magnetic field amplification materials for RFID (Radio Frequency Identification) tags, transformers, inductors, and reactors for high frequency circuits exceeding 20 MHz. For example, it can be attached as a thin sheet to the back of an antenna or receiver/transmitter, and the magnetic flux can be concentrated within the sheet due to its magnetic field amplification properties, or it can be inserted inside a cylindrical or rectangular parallelepiped coil, or it can be inserted into a donut-shaped or yoke-shaped coil. The real number term of the relative magnetic permeability of the coil is improved by winding a conducting wire around the magnetic core, and the result is used as a magnetic material for magnetic field amplification.
　本実施形態の磁場増幅用磁性材料は、高周波領域においても比透磁率の実数項が高いという特徴を有する。例えば周波数１ＭＨｚ以上２０ＭＨｚ以下での比透磁率の実数項は、３以上が好ましく、４以上がより好ましい。又、２０ＭＨｚより大きく１ＧＨｚ未満での比透磁率の実数項は２以上が好ましく、３以上がさらに好ましい。また、本実施形態の磁場増幅用磁性材料は、例えば周波数２０ＭＨｚにおける比透磁率の実数項μ’が３．２以上とすることができ、３．５以上が好ましく、４以上がより好ましく、４．５以上がさらに好ましい。本実施形態の磁場増幅用磁性材料は、周波数２０ＭＨｚにおける比透磁率の実数項μ’は、例えば２００以下とすることができ、１００以下であってもよい。 The magnetic material for magnetic field amplification of this embodiment is characterized in that the real number term of relative magnetic permeability is high even in a high frequency region. For example, the real number term of relative magnetic permeability at a frequency of 1 MHz to 20 MHz is preferably 3 or more, more preferably 4 or more. Further, the real number term of the relative magnetic permeability at a frequency greater than 20 MHz and less than 1 GHz is preferably 2 or more, and more preferably 3 or more. In addition, the magnetic material for magnetic field amplification of the present embodiment can have a real number term μ' of relative magnetic permeability at a frequency of 20 MHz, for example, of 3.2 or more, preferably 3.5 or more, more preferably 4 or more, and 4 or more. .5 or more is more preferable. In the magnetic material for magnetic field amplification of this embodiment, the real number term μ' of relative magnetic permeability at a frequency of 20 MHz can be, for example, 200 or less, and may be 100 or less.
　本実施形態の磁場増幅用磁性材料は、２０ＭＨｚにおけるｔａｎδ（μ”／μ’）及び位相角θは０．３３以下及び７９°以上、０．２９以下及び８０°以上がより好ましく、０．２５以下及び８６°以上がさらに好ましい。また、２０ＭＨｚにおけるｔａｎδ及び位相角θは０．０００１以下及び８８以上であってよい。２０ＭＨｚにおけるｔａｎδ、位相角θが上記範囲内にあると、特にこの周辺の周波数（例えば１０ＭＨｚ以上３０ＭＨｚ以下）で利用する際に、効率が優れた低コストの磁場増幅用磁性材料となるので好ましい。ｔａｎδ（μ”／μ’）及び位相角θは７９°以上であると、素子やシステムに組み込んだ時の発熱を小さくでき、部品等の温度を低くできることで安定性を向上できる傾向がある。ｔａｎδ及び位相角θは０．０００１以下及び８９．９９４以上であると、材料の均質性を高めるためのコストを低減することができる。ここで、複素比透磁率ｔａｎδ及び位相角θは、インピーダンスアナライザ、（ベクトル）ネットワークアナライザ、ＢＨアナライザにより、トロイダル試料のインピーダンスを測定して結果を複素比透磁率、ｔａｎδ及び位相角θに換算する方法、周波数領域によっては（例えば５００ＭＨｚ以上でネットワークアナライザを使用して測定する場合など）Ｓパラメーター法などを用いて測定することができる。 In the magnetic material for magnetic field amplification of the present embodiment, tan δ (μ''/μ') and phase angle θ at 20 MHz are more preferably 0.33 or less and 79° or more, 0.29 or less and 80° or more, and 0.25 More preferably, the tan δ and phase angle θ at 20 MHz are 0.0001 or less and 88 or more. If the tan δ and phase angle θ at 20 MHz are within the above range, especially around this When used at a high frequency (for example, 10 MHz or more and 30 MHz or less), it is preferable because it becomes an efficient and low-cost magnetic material for amplifying magnetic fields.tan δ (μ''/μ') and phase angle θ are 79 degrees or more. There is a tendency that stability can be improved by reducing heat generation when incorporated into elements or systems, and by lowering the temperature of components, etc. When tan δ and phase angle θ are 0.0001 or less and 89.994 or more, the cost for improving the homogeneity of the material can be reduced. Here, the complex relative permeability tan δ and phase angle θ are determined by measuring the impedance of the toroidal sample using an impedance analyzer, a (vector) network analyzer, and a BH analyzer, and converting the results into complex relative permeability, tan δ, and phase angle θ. Depending on the method and frequency domain (for example, when measuring using a network analyzer at 500 MHz or higher), the S-parameter method can be used for measurement.
　また、本実施形態の磁場増幅用磁性材料は、比透磁率の周波数依存性が小さいという特徴も有する。たとえば無線給電という用途では１３．５６ＭＨｚの周波数で給電されるため、その周波数を含む２ＭＨｚ以上２０ＭＨｚ以下の範囲での比透磁率の実数項μ’の変化が小さい磁性材料が優れた効率を有するので好ましく使用できる。また、５ＭＨｚ以下においてさえ比透磁率が大きく変化する材料も多く、この周波数領域での用途などでも、２ＭＨｚ以上２０ＭＨｚ以下の領域で比透磁率の実数項が安定した材料は好ましく使用できる。これらの用途において、上記周波数範囲でμ’の変化が大きい材料は、それに伴いμ”も０からの乖離が大きくなるので、ｔａｎδ及び位相角θも悪化する傾向がある。２ＭＨｚでの比透磁率の実数項に対する２０ＭＨｚでの比透磁率の実数項の比は、０．８以上が好ましく、０．９以上がより好ましい。また、２ＭＨｚでの比透磁率の実数項に対する２０ＭＨｚでの比透磁率の実数項の比は、１．１以下であってよい。この比透磁率の実数項の比が０．８以上であると、エネルギー効率の低下を低減し、磁性材料を組み込んだデバイスの発熱を小さくできる傾向がある。また、比透磁率の実数項の比が１．１以下であると、同デバイスに対する入出力の制御がしやすくなる傾向がある。 Furthermore, the magnetic material for magnetic field amplification of this embodiment also has the characteristic that the frequency dependence of relative magnetic permeability is small. For example, in the application of wireless power supply, power is supplied at a frequency of 13.56 MHz, so a magnetic material with a small change in the real term μ' of relative magnetic permeability in the range of 2 MHz to 20 MHz, including that frequency, has excellent efficiency. It can be used preferably. Furthermore, there are many materials whose relative magnetic permeability changes significantly even at frequencies below 5 MHz, and materials whose real number term of relative magnetic permeability is stable in the range from 2 MHz to 20 MHz can be preferably used for applications in this frequency range. In these applications, materials with large changes in μ' in the above frequency range have a correspondingly large deviation of μ' from 0, so tan δ and phase angle θ also tend to deteriorate. Relative permeability at 2 MHz The ratio of the real term of the relative magnetic permeability at 20 MHz to the real term of the relative magnetic permeability at 20 MHz is preferably 0.8 or more, and more preferably 0.9 or more. The ratio of the real terms of the relative magnetic permeability may be 1.1 or less.If the ratio of the real terms of the relative magnetic permeability is 0.8 or more, the decrease in energy efficiency is reduced and the heat generation of devices incorporating magnetic materials is reduced. There is a tendency that the ratio of the real number term of the relative magnetic permeability is 1.1 or less, which tends to make it easier to control input and output to the device.
　本実施形態の磁場増幅用磁性材料は、樹脂を含んでいてもよい。磁性材料と樹脂の複合材料をボンド磁性材料と呼び、そのボンド磁性材料に含まれる樹脂は、熱硬化性樹脂であっても、熱可塑性樹脂であってもよい。熱可塑性樹脂としては、ポリフェニレンサルファイド（ＰＰＳ）、ポリエーテルエーテルケトン（ＰＥＥＫ）、液晶ポリマー（ＬＣＰ）、ポリアミド（ＰＡ）、ポリプロピレン（ＰＰ）、ポリエチレン（ＰＥ）、熱可塑性エラストマー等が挙げられる。熱硬化性樹脂としては、エポキシ樹脂、フェノール樹脂、ユリア樹脂、メラミン樹脂、グアナミン樹脂、不飽和ポリエステル樹脂、ビニルエステル樹脂、ジアリルフタレート樹脂、ポリウレタン樹脂、シリコーン樹脂、ポリイミド樹脂、アルキド樹脂、フラン樹脂、ジシクロペンタジエン樹脂、アクリル樹脂、アリルカーボネート樹脂、一般にゴムと言われる熱硬化性エラストマーなどが挙げられる。 The magnetic material for magnetic field amplification of this embodiment may contain resin. A composite material of a magnetic material and a resin is called a bonded magnetic material, and the resin contained in the bonded magnetic material may be a thermosetting resin or a thermoplastic resin. Examples of the thermoplastic resin include polyphenylene sulfide (PPS), polyetheretherketone (PEEK), liquid crystal polymer (LCP), polyamide (PA), polypropylene (PP), polyethylene (PE), thermoplastic elastomer, and the like. Thermosetting resins include epoxy resin, phenol resin, urea resin, melamine resin, guanamine resin, unsaturated polyester resin, vinyl ester resin, diallyl phthalate resin, polyurethane resin, silicone resin, polyimide resin, alkyd resin, furan resin, Examples include dicyclopentadiene resin, acrylic resin, allyl carbonate resin, and thermosetting elastomer commonly called rubber.
　ボンド磁性材料中に含まれる樹脂の含有量は、０．１質量％以上９５質量％以下が好ましい。樹脂成分の含有量が０．１質量％以上であることで耐衝撃性がより向上し、９５質量％以下であることで比透磁率や磁化の極端な低下を抑制することができる。さらに、本実施形態のボンド磁性材料において、高比透磁率に耐衝撃性が併せて要求される用途においては、上記と同様な理由で、０．５質量％以上５０質量％以下の範囲がさらに好ましく、特に優れた効率を有する高周波回路用トランスとして用いる場合などは、１質量％以上１５質量％以下の範囲とするのが最も好ましい。また、本実施形態の磁場増幅用磁性材料として比透磁率の実数項が特に高く、超高周波吸収材料として吸収特性を特によくするためには、用途により多少異なるが、同様に１５質量％以下にすることが好ましい。焼結硬化をせず、樹脂を含まない成形体、例えば揮発性有機溶媒などの助剤を使用した圧粉体などは、非常に脆く、負荷が掛かる無線給電コイルやインダクタの磁芯等の磁場増幅用磁性材料、或いは頻繁に持ち運ばれ、衝撃が多く加わる５Ｇ＋や６Ｇモバイル機器に搭載する超高周波吸収材料などに応用することは極めて困難である。又、１．５ＧＰａ以下の圧力で加圧成形された圧粉体のような貫通した空気層を多く含む成形体は、５０℃以上の温度に長時間晒されると、酸化劣化したり、極端に脆化して耐衝撃性が劣化したりするので、高温での用途には不向きな傾向がある。従って、上記のような用途における成形体において、樹脂の含有量は０．１質量％以上９５質量％以下が好ましく、０．５質量％以上５０質量％以下がより好ましく、１質量％以上１５質量％以下がさらに好ましい。 The content of the resin contained in the bonded magnetic material is preferably 0.1% by mass or more and 95% by mass or less. When the content of the resin component is 0.1% by mass or more, the impact resistance is further improved, and when the content is 95% by mass or less, an extreme decrease in relative magnetic permeability and magnetization can be suppressed. Furthermore, for the bonded magnetic material of this embodiment, in applications where high relative magnetic permeability and impact resistance are required, the range of 0.5% by mass to 50% by mass is further increased for the same reason as above. Preferably, when used as a high-frequency circuit transformer having particularly excellent efficiency, it is most preferably in the range of 1% by mass or more and 15% by mass or less. In addition, the real number term of relative magnetic permeability is particularly high as the magnetic material for magnetic field amplification of this embodiment, and in order to have particularly good absorption characteristics as an ultra-high frequency absorbing material, it should be 15% by mass or less, although it varies somewhat depending on the application. It is preferable to do so. Molded bodies that do not undergo sintering and hardening and do not contain resin, such as green compacts that use auxiliary agents such as volatile organic solvents, are extremely brittle and cannot be used in the magnetic fields of wireless power supply coils or magnetic cores of inductors that are subject to loads. It is extremely difficult to apply it to magnetic materials for amplification or ultrahigh frequency absorbing materials installed in 5G+ and 6G mobile devices that are frequently carried around and subjected to many shocks. In addition, compacts containing many penetrating air layers, such as compacts formed under pressure of 1.5 GPa or less, will oxidize and deteriorate if exposed to temperatures of 50°C or higher for long periods of time. Since it becomes brittle and its impact resistance deteriorates, it tends to be unsuitable for applications at high temperatures. Therefore, in the molded article for the above uses, the resin content is preferably 0.1% by mass or more and 95% by mass or less, more preferably 0.5% by mass or more and 50% by mass or less, and 1% by mass or more and 15% by mass or less. % or less is more preferable.
　ボンド磁性材料用の樹脂コンパウンドは、例えば、混練機を用いて、１８０℃以上３００℃以下でα－Ｆｅ含有希土類－鉄－窒素系磁性粉体と樹脂とを混合及び／又は混練することにより得ることができる。例えば、α－Ｆｅ含有希土類－鉄－窒素系磁性粉体および樹脂をミキサーで混合し、次いで二軸押出機で混練し押し出したストランドを空冷した後、ペレタイザーで数ｍｍサイズに切断することでペレット状の本実施形態のボンド磁性材料用樹脂コンパウンドを得ることができる。 A resin compound for a bonded magnetic material can be obtained, for example, by mixing and/or kneading α-Fe-containing rare earth-iron-nitrogen magnetic powder and a resin at a temperature of 180° C. or higher and 300° C. or lower using a kneader. be able to. For example, α-Fe-containing rare earth-iron-nitrogen magnetic powder and resin are mixed in a mixer, then kneaded in a twin-screw extruder, the extruded strand is cooled in air, and then cut into several mm size with a pelletizer to form pellets. The resin compound for bonded magnetic material of this embodiment can be obtained.
　樹脂コンパウンドを、適切な成形機を用いて成形することにより、本実施形態のボンド磁性材料を製造することができる。具体的には例えば、成形機バレル内で溶融した樹脂コンパウンドを、磁場を印可した金型内に射出成形し、磁化容易軸を揃える（配向工程）ことにより、磁場配向成形ボンド磁性材料を得ることができる。また、ペレット状の樹脂コンパウンドをカレンダー加工やホットプレス成形することにより、シート状の磁場増幅用ボンド磁性材料シートや超高周波吸収用ボンド磁性材料シートを作製することができる。これを２０μｍ以上２００μｍ以下の薄さまで圧延することにより、比透磁率の実数項が高い磁場増幅用磁性材料とすることができ、例えばＲＦＩＤタグ用の磁場増幅用磁性材料成形体シートとして好適に利用され、モバイル機器用途の超高周波吸収用磁性材料成形体シートとして利用される。 The bonded magnetic material of this embodiment can be manufactured by molding the resin compound using an appropriate molding machine. Specifically, for example, a resin compound melted in the barrel of a molding machine is injection molded into a mold to which a magnetic field is applied, and the axes of easy magnetization are aligned (orientation process) to obtain a magnetically oriented bonded magnetic material. Can be done. Further, by calendering or hot press molding a pellet-shaped resin compound, a sheet-shaped bonded magnetic material sheet for magnetic field amplification or a bonded magnetic material sheet for ultra-high frequency absorption can be produced. By rolling this to a thickness of 20 μm or more and 200 μm or less, it can be made into a magnetic material for magnetic field amplification with a high real number term of relative magnetic permeability, and can be suitably used as a molded sheet of magnetic material for magnetic field amplification for RFID tags, for example. It is used as a molded sheet of magnetic material for ultra-high frequency absorption in mobile devices.
＜＜超高周波吸収用磁性材料＞＞
　本実施形態の超高周波吸収用磁性材料は、α－Ｆｅ含有希土類－鉄－窒素系磁性粉体を含むことを特徴とする。α－Ｆｅ含有希土類－鉄－窒素系磁性粉体を含むことにより、１ＧＨｚ以上０．１１ＴＨｚ以下の領域でμ”が０より高い比透磁率の虚数項を有し、１ＧＨｚ以上１０ＧＨｚ以下の領域においては、０．８以上のμ”を有するような優れた吸収特性を有していてもよい。 <<Magnetic materials for ultra-high frequency absorption>>
The ultra-high frequency absorbing magnetic material of this embodiment is characterized by containing α-Fe-containing rare earth-iron-nitrogen magnetic powder. By including α-Fe-containing rare earth-iron-nitrogen magnetic powder, it has an imaginary term with a relative magnetic permeability in which μ” is higher than 0 in the range of 1 GHz to 0.11 THz, and may have excellent absorption properties, such as having a μ'' of 0.8 or more.
　α－Ｆｅ含有希土類－鉄－窒素系磁性粉体の平均粒径は０．１μｍ以上１０μｍ以下が好ましい。その理由は上述したとおりであるが、１ＧＨｚ以上の超高周波領域になると、３μｍ以上の粉体は表皮効果により、比透磁率が低下する傾向にあるので、できるだけ粉体粒径は０．１μｍ以上であって、また磁性粒子同士の直接の接触はできるだけ避けなければならない。例えば３０μｍの希土類－鉄－窒素系磁性粉体を超高周波用磁性材料に適用しようとして、５μｍ以下に粉砕したとしても、成形した際、磁性粉体同士が接触して導通してしまい、その導通し合う凝集体の平均的な大きさが３０μｍとなる場合がある。その場合、粉砕前の粉体を使用した場合と比べて高周波特性に対する粒径の効果は同等となってしまい、粉砕した目的を失ってしまう。特に磁性シートを作製する場合、しばしばホットプレスやカレンダー加工のように熱と圧力が同時に掛かる成形法を適用するが、この際、リン化合物のような絶縁膜が磁性粒子表面にしっかりと密着し、成形体マトリックスの中で磁性粒子が凝集しても磁性粒子間は電気的に絶縁されていることが好ましい。凝集しやすい磁性粉体の表面を、フェライトや遷移金属の酸化物のように固くなく、微細で適度に柔らかいリン化合物で被覆することで、熱と圧力を同時に印加して高密度かつ高比透磁率とした高周波用磁性材料とすることができる。 The average particle diameter of the α-Fe-containing rare earth-iron-nitrogen magnetic powder is preferably 0.1 μm or more and 10 μm or less. The reason for this is as mentioned above, but in the ultra-high frequency range of 1 GHz or more, powders with a diameter of 3 μm or more tend to have a lower relative magnetic permeability due to the skin effect, so the powder particle size should be as much as possible than 0.1 μm. Furthermore, direct contact between magnetic particles must be avoided as much as possible. For example, when trying to apply rare earth-iron-nitrogen magnetic powder with a diameter of 30 μm to a magnetic material for ultra-high frequencies, even if it is crushed to 5 μm or less, when molded, the magnetic powders come into contact with each other and conduct. The average size of the aggregates may be 30 μm. In that case, the effect of particle size on high frequency characteristics will be the same as in the case of using powder before pulverization, and the purpose of pulverization will be lost. In particular, when producing magnetic sheets, molding methods that apply heat and pressure at the same time, such as hot pressing or calendering, are often applied, but in this case, an insulating film such as a phosphorous compound tightly adheres to the surface of the magnetic particles. Even if the magnetic particles aggregate in the molded body matrix, it is preferable that the magnetic particles are electrically insulated. By coating the surface of magnetic powder, which tends to aggregate easily, with a fine, moderately soft phosphorus compound that is not hard like ferrite or transition metal oxides, heat and pressure can be applied simultaneously to create high density and high relative permeability. It can be made into a high frequency magnetic material with magnetic property.
　本実施形態の超高周波吸収用磁性材料は、超高周波においても比透磁率の虚数項μ”が高いという特徴を有する。例えば周波数１ＧＨｚ以上２０ＧＨｚ未満での比透磁率の虚数項μ”は、０．２以上が好ましく、０．３以上がより好ましい。又、２０ＧＨｚ以上１ＴＨｚ以下での比透磁率の虚数項μ”は０．０１以上が好ましく、０．１以上がさらに好ましい。また、本実施形態の超高周波吸収用磁性材料は、例えば周波数１０ＧＨｚにおける比透磁率の虚数項μ”が、０．３以上とすることができ、０．５以上が好ましく、０．７以上がより好ましく、０．９以上がさらに好ましい。本実施形態の超高周波吸収用磁性材料は、周波数１０ＧＨｚにおける比透磁率の虚数項μ”は、５以下とすることができ、４以下であってもよい。また、本実施形態の超高周波吸収用磁性材料は、例えば周波数０．１１ＴＨｚにおける比透磁率の虚数項μ”は０．０１以上とすることができ、０．０２以上が好ましく、０．０５以上がより好ましく、０．１以上がさらに好ましい。本実施形態の超高周波吸収用磁性材料は、周波数０．１１ＴＨｚにおける比透磁率の虚数項μ”は、２以下とすることができ、１．５以下であってもよい。加えて、本実施形態の超高周波吸収用磁性材料は、例えば周波数１０ＧＨｚでの比透磁率における虚数項μ”に対する０．１１ＴＨｚでの比透磁率における虚数項μ”の比が、０．０１以上が好ましく、０．１以上がより好ましい。本実施形態の超高周波吸収用磁性材料は、周波数１０ＧＨｚでの比透磁率における虚数項μ”に対する０．１１ＴＨｚでの比透磁率の虚数項μ”の比は５以下が好ましく、１以下がより好ましい。超高周波吸収用磁性材料の周波数１０ＧＨｚでの比透磁率における虚数項μ”に対する０．１１ＴＨｚでの比透磁率における虚数項μ”の比が上記範囲にあることで、広周波数帯域においてより高い吸収特性を示すことができる。 The ultra-high frequency absorbing magnetic material of this embodiment has a feature that the imaginary term μ'' of the relative magnetic permeability is high even at ultra-high frequencies. For example, the imaginary term μ'' of the relative magnetic permeability at a frequency of 1 GHz or more and less than 20 GHz is 0. .2 or more is preferable, and 0.3 or more is more preferable. Further, the imaginary term μ'' of the relative magnetic permeability at a frequency of 20 GHz or more and 1 THz or less is preferably 0.01 or more, and more preferably 0.1 or more. The imaginary term μ'' of the relative magnetic permeability can be 0.3 or more, preferably 0.5 or more, more preferably 0.7 or more, and even more preferably 0.9 or more. In the ultra-high frequency absorbing magnetic material of this embodiment, the imaginary term μ'' of the relative magnetic permeability at a frequency of 10 GHz can be 5 or less, and may be 4 or less. For example, the imaginary term μ'' of relative magnetic permeability at a frequency of 0.11 THz of the magnetic material for use can be set to 0.01 or more, preferably 0.02 or more, more preferably 0.05 or more, and 0.1 or more. More preferred. In the ultra-high frequency absorbing magnetic material of this embodiment, the imaginary term μ'' of the relative magnetic permeability at a frequency of 0.11 THz can be 2 or less, and may be 1.5 or less. In the ultra-high frequency absorbing magnetic material of the form, for example, the ratio of the imaginary term μ'' in the relative magnetic permeability at a frequency of 10 GHz to the imaginary term μ'' in the relative magnetic permeability at a frequency of 0.11 THz is preferably 0.01 or more, and 0.01 or more. More preferably, it is 1 or more. In the ultra-high frequency absorbing magnetic material of the present embodiment, the ratio of the imaginary term μ'' of the relative magnetic permeability at 0.11 THz to the imaginary term μ'' of the relative magnetic permeability at a frequency of 10 GHz is 5 or less. Preferably, 1 or less is more preferable.The ratio of the imaginary term μ'' in the relative magnetic permeability at 0.11 THz to the imaginary term μ'' in the relative magnetic permeability at a frequency of 10 GHz of the ultra-high frequency absorbing magnetic material is within the above range. , can exhibit higher absorption characteristics in a wide frequency band.
　本実施形態の超高周波吸収用磁性材料は、α－Ｆｅ含有希土類－鉄－窒素系磁性粉体を含むことにより、１ＧＨｚ～１ＴＨｚまで、超広周波数帯域超高周波吸収が可能で、例えば、このような超高周波で使用が期待される六方晶フェライト、ホウ化物、イプシロン酸化鉄などの一軸結晶磁気異方性材料のように、帯域幅１０ＧＨｚ程度での狭帯域で低比透磁率である磁性材料とは一線を画する。酸化物材料より電気抵抗率は小さいが、金属系材料より高抵抗であり、１ＴＨｚまで高周波特性が保たれる面内結晶磁気異方性材料にとって、磁性粉体に高電気抵抗率のリン化合物が含有されていることが大きな特徴である。 The ultra-high frequency absorbing magnetic material of this embodiment contains α-Fe-containing rare earth-iron-nitrogen magnetic powder, and is therefore capable of absorbing ultra-high frequencies in an ultra-wide frequency range from 1 GHz to 1 THz. Magnetic materials with low relative magnetic permeability in a narrow band with a bandwidth of about 10 GHz, such as uniaxial magnetocrystalline anisotropic materials such as hexagonal ferrite, borides, and epsilon iron oxide, which are expected to be used at extremely high frequencies. draws the line. For in-plane magnetocrystalline anisotropic materials, which have lower electrical resistivity than oxide materials but higher resistance than metallic materials and maintain high frequency characteristics up to 1 THz, it is important to use phosphorus compounds with high electrical resistivity in magnetic powder. A major feature is that it is contained.
　超高周波吸収用磁性材料のより具体的な用途としては、５Ｇ（第５世代移動通信システム：５ｔｈ　Ｇｅｎｅｒａｔｉｏｎ　Ｍｏｂｉｌｅ　Ｃｏｍｍｕｎｉｃａｔｉｏｎ　Ｓｙｓｔｅｍ）、　５Ｇ＋（第５世代プラス移動通信システム：５ｔｈ　Ｇｅｎｅｒａｔｉｏｎ　Ｐｌｕｓ　Ｍｏｂｉｌｅ　Ｃｏｍｍｕｎｉｃａｔｉｏｎ　Ｓｙｓｔｅｍ）及び６Ｇ（第６世代移動通信システム：６ｔｈ　Ｇｅｎｅｒａｔｉｏｎ　Ｍｏｂｉｌｅ　Ｃｏｍｍｕｎｉｃａｔｉｏｎ　Ｓｙｓｔｅｍ）に適用するモバイル通信機、携帯電話小型基地局及びクラウド基地局、それらの機器、デバイス、アンテナなどのインフラ機材に適用する超高周波信号やスプリアス吸収用の部材、ＩＴＳ（高度道路交通システム：Ｉｎｔｅｌｌｉｇｅｎｔ　Ｔｒａｎｓｐｏｒｔ　Ｓｙｓｔｅｍｓ）、ワイヤレスＨＤＭＩ（登録商標）（ワイヤレス高精細度マルチメディアインターフェース：Ｈｉｇｈ－Ｄｅｆｉｎｉｔｉｏｎ　Ｍｕｌｔｉｍｅｄｉａ　Ｉｎｔｅｒｆａｃｅ）、無線ＬＡＮ（ワイヤレスローカルエリアネットワーク：Ｌｏｃａｌ　Ａｒｅａ　Ｎｅｔｗｏｒｋ）、衛星放送（Ｋａ－バンド）などに用いられる機器・デバイス用超高周波信号やスプリアス吸収用の部材、パーソナルコンピュータの主に第２～第７高調波を除去する電磁ノイズ吸収部材などが挙げられる。 More specific applications of magnetic materials for ultra-high frequency absorption include 5G (5th Generation Mobile Communication System), 5G+ (5th Generation Plus Mobile Communication System), and 5G+ (5th Generation Plus Mobile Communication System). ile Communication System) and 6G (6th Generation Mobile Communication System) Ultra-high frequency signals and spurious signals applied to infrastructure equipment such as mobile communication devices, small mobile phone base stations and cloud base stations, their equipment, devices, antennas, etc. Absorption members, ITS (Intelligent Transport Systems), Wireless HDMI (registered trademark) (Wireless High-Definition Multimedia Interface), Wireless LAN (Wireless Local Area Network: LoC) al Area Network ), materials for absorbing ultra-high frequency signals and spurious signals for equipment and devices used in satellite broadcasting (Ka-band), etc., and electromagnetic noise absorbing materials for personal computers that mainly remove the 2nd to 7th harmonics. .
　本実施形態の超高周波吸収用磁性材料は、樹脂を含んでいてもよい。磁性材料と樹脂の複合材料をボンド磁性材料と呼び、そのボンド磁性材料に含まれる樹脂は、熱硬化性樹脂であっても、熱可塑性樹脂であってもよい。熱可塑性樹脂としては、ポリフェニレンサルファイド（ＰＰＳ）、ポリエーテルエーテルケトン（ＰＥＥＫ）、液晶ポリマー（ＬＣＰ）、ポリアミド（ＰＡ）、ポリプロピレン（ＰＰ）、ポリエチレン（ＰＥ）、熱可塑性エラストマー等が挙げられる。熱硬化性樹脂としては、エポキシ樹脂、フェノール樹脂、ユリア樹脂、メラミン樹脂、グアナミン樹脂、不飽和ポリエステル樹脂、ビニルエステル樹脂、ジアリルフタレート樹脂、ポリウレタン樹脂、シリコーン樹脂、ポリイミド樹脂、アルキド樹脂、フラン樹脂、ジシクロペンタジエン樹脂、アクリル樹脂、アリルカーボネート樹脂、一般にゴムと言われる熱硬化性エラストマーなどが挙げられる。 The ultra-high frequency absorbing magnetic material of this embodiment may contain resin. A composite material of a magnetic material and a resin is called a bonded magnetic material, and the resin contained in the bonded magnetic material may be a thermosetting resin or a thermoplastic resin. Examples of the thermoplastic resin include polyphenylene sulfide (PPS), polyetheretherketone (PEEK), liquid crystal polymer (LCP), polyamide (PA), polypropylene (PP), polyethylene (PE), thermoplastic elastomer, and the like. Thermosetting resins include epoxy resin, phenol resin, urea resin, melamine resin, guanamine resin, unsaturated polyester resin, vinyl ester resin, diallyl phthalate resin, polyurethane resin, silicone resin, polyimide resin, alkyd resin, furan resin, Examples include dicyclopentadiene resin, acrylic resin, allyl carbonate resin, and thermosetting elastomer commonly called rubber.
　ボンド磁性材料中に含まれる樹脂の含有量は、０．１質量％以上９５質量％以下が好ましい。樹脂成分の含有量が０．１質量％以上であることで耐衝撃性がより向上し、９５質量％以下であることで比透磁率や磁化の極端な低下を抑制することができる。さらに、本実施形態のボンド磁性材料において、高比透磁率に耐衝撃性が併せて要求される用途においては、上記と同様な理由で、０．５質量％以上５０質量％以下の範囲がより好ましく、特に優れた効率を有する高周波回路用トランスとして用いる場合などは、１質量％以上１５質量％以下の範囲とするのがさらに好ましい。また、本実施形態の磁場増幅用磁性材料として比透磁率の実数項が特に高く、超高周波吸収材料として吸収特性を特によくするためには、用途により多少異なるが、同様に１５質量％以下にすることが好ましい。焼結硬化をせず、樹脂を含まない成形体、例えば揮発性有機溶媒などの助剤を使用した圧粉体などは、非常に脆く、負荷が掛かる無線給電コイルやインダクタの磁芯等の磁場増幅用磁性材料、或いは頻繁に持ち運ばれ、衝撃が多く加わる５Ｇ＋や６Ｇモバイル機器に搭載する超高周波吸収材料などに応用することは極めて困難である。又、１．５ＧＰａ以下の圧力で加圧成形された圧粉体のような貫通した空気層を多く含む成形体は、５０℃以上の温度に長時間晒されると、酸化劣化したり、極端に脆化して耐衝撃性が劣化したりするので、高温での用途には不向きな傾向がある。従って、上記のような用途における成形体において、樹脂の含有量は０．１質量％以上９５質量％以下が好ましく、０．５質量％以上５０質量％以下がより好ましく、１質量％以上１５質量％以下がさらに好ましい。 The content of the resin contained in the bonded magnetic material is preferably 0.1% by mass or more and 95% by mass or less. When the content of the resin component is 0.1% by mass or more, the impact resistance is further improved, and when the content is 95% by mass or less, an extreme decrease in relative magnetic permeability and magnetization can be suppressed. Furthermore, for the bonded magnetic material of this embodiment, in applications where high relative magnetic permeability and impact resistance are required, the range of 0.5% by mass or more and 50% by mass or less is more suitable for the same reason as above. Preferably, when used as a high-frequency circuit transformer having particularly excellent efficiency, the content is more preferably in the range of 1% by mass or more and 15% by mass or less. In addition, the real number term of relative magnetic permeability is particularly high as the magnetic material for magnetic field amplification of this embodiment, and in order to have particularly good absorption characteristics as an ultra-high frequency absorbing material, it should be 15% by mass or less, although it varies somewhat depending on the application. It is preferable to do so. Molded bodies that do not undergo sintering and hardening and do not contain resin, such as green compacts that use auxiliary agents such as volatile organic solvents, are extremely brittle and cannot be used in the magnetic fields of wireless power supply coils or magnetic cores of inductors that are subject to loads. It is extremely difficult to apply it to magnetic materials for amplification or ultrahigh frequency absorbing materials installed in 5G+ and 6G mobile devices that are frequently carried around and subjected to many shocks. In addition, compacts containing many penetrating air layers, such as compacts formed under pressure of 1.5 GPa or less, will oxidize and deteriorate if exposed to temperatures of 50°C or higher for long periods of time. Since it becomes brittle and its impact resistance deteriorates, it tends to be unsuitable for applications at high temperatures. Therefore, in the molded article for the above uses, the resin content is preferably 0.1% by mass or more and 95% by mass or less, more preferably 0.5% by mass or more and 50% by mass or less, and 1% by mass or more and 15% by mass or less. % or less is more preferable.
　ボンド磁性材料用の樹脂コンパウンドは、例えば、混練機を用いて、１８０℃以上３００℃以下でリン化合物と、α－Ｆｅ含有希土類－鉄－窒素系磁性粉体および樹脂とを混合及び／又は混練する、または、α－Ｆｅ含有希土類－鉄－窒素系磁性粉体および樹脂を混合及び／又は混練することにより得ることができる。例えば、α－Ｆｅ含有希土類－鉄－窒素系磁性粉体および樹脂をミキサーで混合し、次いで二軸押出機で混練し押し出したストランドを空冷した後、ペレタイザーで数ｍｍサイズに切断することでペレット状の本実施形態のボンド磁性材料用樹脂コンパウンドを得ることができる。 A resin compound for a bonded magnetic material can be prepared by mixing and/or kneading a phosphorus compound, an α-Fe-containing rare earth-iron-nitrogen magnetic powder, and a resin at a temperature of 180°C or higher and 300°C or lower using a kneader, for example. Alternatively, it can be obtained by mixing and/or kneading α-Fe-containing rare earth-iron-nitrogen magnetic powder and a resin. For example, α-Fe-containing rare earth-iron-nitrogen magnetic powder and resin are mixed in a mixer, then kneaded in a twin-screw extruder, the extruded strand is cooled in air, and then cut into several mm size with a pelletizer to form pellets. The resin compound for bonded magnetic material of this embodiment can be obtained.
　樹脂コンパウンドを、適切な成形機を用いて成形することにより、本実施形態のボンド磁性材料を製造することができる。具体的には例えば、成形機バレル内で溶融した樹脂コンパウンドを、磁場を印可した金型内に射出成形し、磁化容易軸を揃える（配向工程）ことにより、磁場配向成形ボンド磁性材料を得ることができる。また、ペレット状の樹脂コンパウンドをカレンダー加工やホットプレス成形することにより、シート状の磁場増幅用ボンド磁性材料シートや超高周波吸収用ボンド磁性材料シートを作製することができる。これを２０μｍ以上２００μｍ以下の薄さまで圧延することにより、比透磁率の実数項が高い磁場増幅用磁性材料とすることができ、例えばＲＦＩＤタグ用の磁場増幅用磁性材料成形体シートとして好適に利用され、モバイル機器用途の超高周波吸収用磁性材料成形体シートとして利用される。 The bonded magnetic material of this embodiment can be manufactured by molding the resin compound using an appropriate molding machine. Specifically, for example, a resin compound melted in the barrel of a molding machine is injection molded into a mold to which a magnetic field is applied, and the axes of easy magnetization are aligned (orientation process) to obtain a magnetically oriented bonded magnetic material. Can be done. Further, by calendering or hot press molding a pellet-shaped resin compound, a sheet-shaped bonded magnetic material sheet for magnetic field amplification or a bonded magnetic material sheet for ultra-high frequency absorption can be produced. By rolling this to a thickness of 20 μm or more and 200 μm or less, it can be made into a magnetic material for magnetic field amplification with a high real number term of relative magnetic permeability, and can be suitably used as a molded sheet of magnetic material for magnetic field amplification for RFID tags, for example. It is used as a molded sheet of magnetic material for ultra-high frequency absorption in mobile devices.
＜＜α－Ｆｅ含有希土類－鉄－窒素系磁性粉体の製造方法＞＞
　本実施形態のα－Ｆｅ含有希土類－鉄－窒素系磁性粉体の製造方法は、希土類Ｒ（ＲはＹ、Ｃｅ、Ｐｒ、Ｎｄ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｌｕ、およびＳｍからなる群から選択される少なくとも１種であって、Ｓｍを含む場合はＲ成分全体に対してＳｍが５０原子％未満である）、Ｆｅ、およびＮを含む希土類－鉄－窒素系磁性粉体、水、ならびにリン含有物を含むスラリーに対して無機酸を添加することで、希土類－鉄－窒素系磁性粉体上にリン化合物被覆部を形成して、リン化合物被覆部を有する希土類－鉄－窒素系磁性粉体を得るリン処理工程、およびリン化合物被覆部を有する希土類－鉄－窒素系磁性粉体を、酸素含有雰囲気下で３５０℃以上６００℃以下で熱処理する酸化工程を含むことを特徴とする。 <<Method for producing α-Fe-containing rare earth-iron-nitrogen magnetic powder>>
The method for producing α-Fe-containing rare earth-iron-nitrogen magnetic powder of the present embodiment includes rare earth R (R is Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Rare earth-iron-nitrogen magnetic powder containing at least one member selected from the group consisting of Sm (if Sm is included, Sm is less than 50 atomic % with respect to the entire R component), Fe, and N. By adding an inorganic acid to a slurry containing a phosphorus-containing material, water, and a phosphorus-containing material, a phosphorus compound coating is formed on the rare earth-iron-nitrogen magnetic powder, and a rare earth-containing phosphorus compound-coated portion is formed on the rare earth-iron-nitrogen magnetic powder. Includes a phosphorus treatment step for obtaining iron-nitrogen magnetic powder, and an oxidation step in which the rare earth-iron-nitrogen magnetic powder having a phosphorus compound coating is heat-treated at 350°C or higher and 600°C or lower in an oxygen-containing atmosphere. It is characterized by
［リン処理工程］
　リン処理工程では、ＲとＦｅとＮを含む希土類－鉄－窒素系磁性粉体、水、およびリン含有物を含むスラリーに対して無機酸を添加して、リン化合物被覆部を有する希土類－鉄－窒素系磁性粉体を得る。リン化合物被覆部を有する希土類－鉄－窒素系磁性粉体は、希土類－鉄－窒素系磁性粉体に含まれる金属成分（例えば鉄やネオジム等）とリン含有物に含まれるリン成分（例えばリン酸）が反応することによりリン化合物（例えばリン酸鉄、リン酸ネオジム等）が析出することによって形成される。また、リン化合物被覆部を有する希土類－鉄－窒素系磁性粉体は、希土類－鉄－窒素系磁性粉体の表面でリン化合物が析出することにより希土類－鉄－窒素系磁性粉体の少なくとも一部の表面を被覆（このような被覆を「リン化合物被覆」という。このような被覆により形成された部分を「リン化合物被覆部」という）することにより形成することが好ましい。なお、本実施形態によると、無機酸を添加してスラリーのｐＨを調整することによって、無機酸を添加しない場合と比較して、リン化合物の析出量を多くすることができる。そのため、被覆部の厚み（膜厚ともいう）が厚いリン化合物被覆希土類－鉄－窒素系磁性粉体が得られ、ｔａｎδ及び位相角θが向上し、磁場増幅特性が向上する。また、本実施形態によると、溶媒を水とすることによって、有機溶媒を使用する場合と比較して、粒径が小さいリン酸塩などのリン化合物が析出するので、緻密なリン化合物被覆部を有する希土類－鉄－窒素系磁性粉体が得られ、高周波領域での優れた効率や超高周波領域での優れた吸収特性が得られやすい傾向がある。 [Phosphorus treatment process]
In the phosphorus treatment step, an inorganic acid is added to a slurry containing a rare earth-iron-nitrogen magnetic powder containing R, Fe, and N, water, and a phosphorus-containing material to form a rare-earth-iron material having a phosphorus compound coating. - Obtain nitrogen-based magnetic powder. The rare earth-iron-nitrogen magnetic powder having a phosphorus compound coating is composed of metal components (e.g., iron, neodymium, etc.) contained in the rare-earth-iron-nitrogen magnetic powder and phosphorus components (e.g., phosphorus) contained in the phosphorus-containing material. It is formed when a phosphorus compound (for example, iron phosphate, neodymium phosphate, etc.) is precipitated by the reaction of phosphorus (acid). In addition, the rare earth-iron-nitrogen magnetic powder having a phosphorus compound-coated portion is formed by precipitating a phosphorus compound on the surface of the rare-earth-iron-nitrogen magnetic powder. It is preferable to form this by coating the surface of the part (such a coating is referred to as a "phosphorus compound coating"; a part formed by such coating is referred to as a "phosphorus compound coated part"). Note that, according to the present embodiment, by adding an inorganic acid to adjust the pH of the slurry, it is possible to increase the amount of precipitated phosphorus compounds compared to the case where no inorganic acid is added. Therefore, a phosphorus compound-coated rare earth-iron-nitrogen magnetic powder having a thick coating portion (also referred to as film thickness) can be obtained, improving tan δ and phase angle θ, and improving magnetic field amplification characteristics. Furthermore, according to the present embodiment, by using water as the solvent, phosphorus compounds such as phosphates with smaller particle sizes are precipitated compared to the case where an organic solvent is used. A rare earth-iron-nitrogen magnetic powder having the following characteristics is obtained, and tends to have excellent efficiency in a high frequency region and excellent absorption characteristics in an ultra-high frequency region.
　ＲとＦｅとＮを含む希土類－鉄－窒素系磁性粉体、水、およびリン含有物を含むスラリーを作製する方法は、特に限定されないが、例えば、希土類－鉄－窒素系磁性粉体と、水を溶媒としてリン含有物を含むリン含有物溶液とを混合することによって得られる。スラリー中の希土類－鉄－窒素系磁性粉体の含有量は、１質量％以上５０質量％以下が好ましく、生産性の点から５質量％以上２０質量％以下がより好ましい。スラリー中のリン含有物の含有量は特に限定されないが、リン含有物がリン酸であり、水素とリン酸成分（ＰＯ４）のみで構成されている場合の含有量は、ＰＯ４換算量で、例えば０．０１質量％以上１０質量％以下であり、金属成分とリン酸成分との反応性や生産性の点から０．０５質量％以上５質量％以下が好ましい。 A method for producing a slurry containing rare earth-iron-nitrogen magnetic powder containing R, Fe, and N, water, and a phosphorus-containing substance is not particularly limited, but for example, rare earth-iron-nitrogen magnetic powder, It is obtained by mixing a phosphorus-containing substance solution containing a phosphorus-containing substance using water as a solvent. The content of the rare earth-iron-nitrogen magnetic powder in the slurry is preferably 1% by mass or more and 50% by mass or less, and more preferably 5% by mass or more and 20% by mass or less from the viewpoint of productivity. The content of the phosphorus-containing substance in the slurry is not particularly limited, but when the phosphorus-containing substance is phosphoric acid and is composed only of hydrogen and phosphoric acid components (PO 4 ), the content is expressed as PO 4 equivalent amount. , for example, from 0.01% by mass to 10% by mass, and preferably from 0.05% by mass to 5% by mass from the viewpoint of reactivity between the metal component and the phosphoric acid component and productivity.
　リン含有物としては、リン単体及びその組成物、オルトリン酸などのリン酸化合物、リンタングステン酸、リンモリブデン酸等のヘテロポリ酸化合物、リン酸化合物やヘテロポリ酸化合物などのリン含有酸化合物と金属イオンまたはアンモニウムイオンとの塩、リン酸エステル、亜リン酸エステル、ホスフィンオキシド等の有機リン化合物、リン化鉄、リン青銅、Ｆｅ－Ｂ－Ｐ－ＣｕやＦｅ－Ｎｂ－Ｂ－Ｐ系合金などのリン含有金属等が挙げられる。 Examples of phosphorus-containing substances include phosphorus alone and its compositions, phosphoric acid compounds such as orthophosphoric acid, heteropolyacid compounds such as phosphotungstic acid and phosphomolybdic acid, phosphorus-containing acid compounds such as phosphoric acid compounds and heteropolyacid compounds, and metal ions. Or salts with ammonium ions, organic phosphorus compounds such as phosphate esters, phosphite esters, phosphine oxides, iron phosphide, phosphor bronze, Fe-BP-Cu and Fe-Nb-BP alloys, etc. Examples include phosphorus-containing metals.
　リン含有物がリン酸化合物の場合、リン酸水溶液はリン酸化合物と水を混合することによって得られる。リン酸化合物としては、例えば、オルトリン酸、リン酸二水素ナトリウム、リン酸一水素ナトリウム、リン酸二水素アンモニウム、リン酸一水素アンモニウム、リン酸亜鉛、リン酸カルシウムなどのリン酸塩系、次亜リン酸系、次亜リン酸塩系、ピロリン酸系、ポリリン酸系などの無機リン酸等、有機リン酸が挙げられる。これらは１種のみを用いてもよく、２種以上を併用してもよい。また、被覆部の耐水性、耐食性や磁性粉体の磁気特性を向上する目的で、モリブデン酸塩、タングステン酸塩、バナジン酸塩、クロム酸塩などのオキソ酸塩等、硝酸ナトリウム、亜硝酸ナトリウムなどの酸化剤等、ＥＤＴＡなどのキレート剤等を添加剤として用いることができる。リン含有物のなかでも、反応の制御、被覆量の制御の観点で、オルトリン酸、ピロリン酸、ポリリン酸などの無機リン酸、および、それらとＮａ、Ｃａ、Ｐｂ、Ｚｎ、Ｆｅ、Ｙ、Ｃｅ、Ｐｒ、Ｎｄ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｌｕ、Ｓｍ、アンモニウムなどとのリン酸塩などのリン酸化合物が好ましい。 When the phosphorus-containing material is a phosphoric acid compound, a phosphoric acid aqueous solution can be obtained by mixing the phosphoric acid compound and water. Examples of phosphoric acid compounds include orthophosphoric acid, sodium dihydrogen phosphate, sodium monohydrogen phosphate, ammonium dihydrogen phosphate, ammonium monohydrogen phosphate, zinc phosphate, calcium phosphate, and hypophosphorous. Examples include inorganic phosphoric acids such as acid-based, hypophosphite-based, pyrophosphoric acid-based, and polyphosphoric acid-based acids, and organic phosphoric acids. These may be used alone or in combination of two or more. In addition, for the purpose of improving the water resistance and corrosion resistance of the coating and the magnetic properties of magnetic powder, we use oxoacid salts such as molybdate, tungstate, vanadate, and chromate, sodium nitrate, and sodium nitrite. Oxidizing agents such as EDTA, chelating agents such as EDTA, etc. can be used as additives. Among phosphorus-containing substances, inorganic phosphoric acids such as orthophosphoric acid, pyrophosphoric acid, and polyphosphoric acid, as well as Na, Ca, Pb, Zn, Fe, Y, and Ce, are recommended from the viewpoint of reaction control and coating amount control. Preferred are phosphoric acid compounds such as phosphates with , Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, Sm, ammonium, etc.
　リン酸水溶液におけるリン酸の濃度（ＰＯ４換算量）は、５質量％以上５０質量％以下が好ましく、リン酸化合物の溶解度、保存安定性や化成処理のし易さの点から１０質量％以上３０質量％以下がより好ましい。リン酸水溶液のｐＨは、１以上４．５以下が好ましく、リン酸塩の析出速度を制御しやすい点から１．５以上４以下であることがより好ましい。ｐＨは希塩酸、希硫酸などにより調整できる。 The concentration of phosphoric acid in the phosphoric acid aqueous solution (PO 4 equivalent amount) is preferably 5% by mass or more and 50% by mass or less, and 10% by mass or more from the viewpoint of solubility of the phosphoric acid compound, storage stability, and ease of chemical conversion treatment. More preferably, it is 30% by mass or less. The pH of the phosphoric acid aqueous solution is preferably 1 or more and 4.5 or less, and more preferably 1.5 or more and 4 or less from the viewpoint of easy control of the precipitation rate of phosphate. The pH can be adjusted using dilute hydrochloric acid, dilute sulfuric acid, etc.
　リン処理工程においては、無機酸を添加することによりスラリーを酸性にするが、ｐＨを１以上４．５以下に調整することが好ましく、１．６以上３．９以下に調整することがより好ましく、２以上３以下に調整することがさらに好ましい。ｐＨが１未満では、局部的に多量に析出したリン化合物を起点として希土類－鉄－窒素系磁性粉体同士が凝集することにより、高周波領域でｔａｎδ及び位相角θが悪化し、超高周波領域でμ”が低下する傾向がある。ｐＨが４．５を超えると、リン酸塩などのリン化合物の析出量が減少することにより、高周波領域でｔａｎδ及び位相角θが悪化し、超高周波領域ではμ”が低下する傾向がある。添加する無機酸としては、塩酸、硝酸、硫酸、ほう酸、フッ化水素酸が挙げられる。リン処理工程中は、上記ｐＨの範囲となるように、無機酸を随時添加することが好ましい。廃液処理の観点から無機酸を使用するが、目的に応じて有機酸を併用することができる。有機酸としては酢酸、蟻酸、酒石酸等が挙げられる。 In the phosphorus treatment step, the slurry is made acidic by adding an inorganic acid, and the pH is preferably adjusted to 1 or more and 4.5 or less, more preferably 1.6 or more and 3.9 or less. , more preferably adjusted to 2 or more and 3 or less. When the pH is less than 1, the rare earth-iron-nitrogen magnetic powders aggregate starting from locally precipitated phosphorus compounds in large quantities, resulting in worsening of tan δ and phase angle θ in the high frequency range, and in the ultra-high frequency range. μ" tends to decrease. When the pH exceeds 4.5, the amount of precipitated phosphorus compounds such as phosphate decreases, resulting in worsening of tan δ and phase angle θ in the high frequency region, and in the ultra-high frequency region. μ” tends to decrease. Examples of the inorganic acid to be added include hydrochloric acid, nitric acid, sulfuric acid, boric acid, and hydrofluoric acid. During the phosphorus treatment step, it is preferable to add an inorganic acid as needed to maintain the above pH range. Although inorganic acids are used from the viewpoint of waste liquid treatment, organic acids can be used in combination depending on the purpose. Examples of organic acids include acetic acid, formic acid, and tartaric acid.
　リン処理工程は、得られる磁性粉体におけるリンの含有量が０．０２質量％以上となるように行うこともできる。リン処理工程において得られる磁性粉体におけるリンの含有量は、０．０５質量％以上が好ましく、０．１５質量％以上がより好ましい。リン処理工程において得られる磁性粉体におけるリンの含有量は４質量％以下が好ましく、２質量％以下がより好ましく、１質量％以下がさらに好ましい。リンの含有量が０．０２質量％以上であると、リン化合物による被覆の効果がより大きくなる傾向があり、４質量％以下であると、リン化合物を起点として希土類－鉄－窒素系磁性粉体同士が凝集して高周波領域でｔａｎδ及び位相角θが悪化したり、超高周波領域でμ”が低下したりすることを抑制できる傾向がある。特に優れた効率を有する磁場増幅用磁性材料や、優れた吸収特性を有する超高周波吸収用磁性材料を作製する場合は、リン含有量は０．１５質量％以上１質量％以下が好ましい。なお、磁性粉体全体のバルクのリン含有量は、ＩＣＰ－ＡＥＳ（ＩＣＰ発光分光分析法）を用いて測定できる。また、リン化合物被覆粉体における磁性粉体相やリン化合物被覆部の局所的なリン含有量はＳＴＥＭ－ＥＤＸライン分析を用いて測定することができる。また、リン化合物被覆部中のリン（Ｐ）原子濃度は、好ましくは１原子％以上、より好ましくは５原子％以上である。また、リン化合物被覆部中のＰ原子濃度は、２５原子％以下であってよく、好ましくは１５原子％以下である。リン化合物被覆部中のリン含有量が、１原子％未満であると、リン化合物の電気的絶縁性が機能しづらい傾向があり、２５原子％を超えると、高周波領域における比透磁率の実数項及び超高周波領域における比透磁率の虚数項が低下するだけでなく、耐食性に対する性能も低下する傾向がある。 The phosphorus treatment step can also be carried out so that the phosphorus content in the obtained magnetic powder is 0.02% by mass or more. The phosphorus content in the magnetic powder obtained in the phosphorus treatment step is preferably 0.05% by mass or more, more preferably 0.15% by mass or more. The phosphorus content in the magnetic powder obtained in the phosphorus treatment step is preferably 4% by mass or less, more preferably 2% by mass or less, and even more preferably 1% by mass or less. When the phosphorus content is 0.02% by mass or more, the effect of coating with the phosphorus compound tends to be greater, and when it is 4% by mass or less, the rare earth-iron-nitrogen magnetic powder starts from the phosphorus compound. There is a tendency that it is possible to suppress the aggregation of bodies, which deteriorates tan δ and phase angle θ in the high frequency range, and decreases μ'' in the ultra high frequency range.In particular, magnetic materials for magnetic field amplification with excellent efficiency and When producing a magnetic material for ultra-high frequency absorption having excellent absorption properties, the phosphorus content is preferably 0.15% by mass or more and 1% by mass or less.The bulk phosphorus content of the entire magnetic powder is: It can be measured using ICP-AES (ICP emission spectroscopy).In addition, the local phosphorus content in the magnetic powder phase and phosphorus compound-coated parts of phosphorus compound-coated powder can be measured using STEM-EDX line analysis. In addition, the phosphorus (P) atom concentration in the phosphorus compound coated part is preferably 1 at% or more, more preferably 5 at% or more.In addition, the P atom concentration in the phosphorus compound coated part is , may be 25 atom % or less, preferably 15 atom % or less. If the phosphorus content in the phosphorus compound coating is less than 1 atom %, the electrical insulation properties of the phosphorus compound tend to be difficult to function. If it exceeds 25 at %, not only the real term of relative magnetic permeability in the high frequency region and the imaginary term of the relative magnetic permeability in the ultrahigh frequency region tend to decrease, but also the corrosion resistance performance tends to decrease.
　リン処理工程は、得られる磁性粉体の表面に存在するリン化合物被覆部において、希土類（Ｒ）原子濃度が、母材である希土類（Ｒ）－鉄－窒素系磁性粉体中のＲ原子濃度より高い領域（Ｒ高濃度領域）を有するように行われても良い。Ｒ高濃度領域中のＲ原子濃度は、α－Ｆｅ含有希土類－鉄－窒素系磁性粉体中のコア領域のＲ原子濃度の１．０５倍以上とすることができ、１．１倍以上が好ましく、１．２倍以上がより好ましく、１．５倍以上がさらに好ましい。また、Ｒ高濃度領域中のＲ原子濃度は、例えばα－Ｆｅ含有希土類－鉄－窒素系磁性粉体中のコア領域のＲ原子濃度の４倍以下とすることができる。ここで、Ｒ高濃度領域は、α－Ｆｅ含有希土類－鉄－窒素系磁性粉体のＳＴＥＭ－ＥＤＸライン分析において、Ｐ（リン）のピークを示す層を包含する領域である。Ｒ高濃度領域の厚みは例えば１ｎｍ以上とすることができ、３ｎｍ以上１５０ｎｍ以下が好ましく、１０ｎｍ以上１００ｎｍ以下がより好ましく、２０ｎｍ以上８０ｎｍ以下がさらに好ましい。Ｒ高濃度領域中の各元素の原子濃度（原子％）は、ＳＴＥＭ－ＥＤＸライン分析におけるリン化合物被覆部中の原子濃度を平均することにより求められる。希土類元素（Ｒ）としては例えばＮｄであってよく、その場合、Ｎｄ高濃度領域として、Ｎｄ原子濃度を基準として評価することができる。 In the phosphorus treatment step, the rare earth (R) atom concentration in the phosphorus compound coating portion existing on the surface of the obtained magnetic powder is the same as the R atom concentration in the rare earth (R)-iron-nitrogen magnetic powder that is the base material. It may also be done to have a higher region (R high concentration region). The R atom concentration in the R high concentration region can be 1.05 times or more the R atom concentration in the core region in the α-Fe-containing rare earth-iron-nitrogen magnetic powder, and 1.1 times or more. It is preferably 1.2 times or more, more preferably 1.5 times or more. Further, the R atom concentration in the R high concentration region can be, for example, four times or less than the R atom concentration in the core region of the α-Fe-containing rare earth-iron-nitrogen magnetic powder. Here, the R high concentration region is a region including a layer exhibiting a P (phosphorus) peak in STEM-EDX line analysis of α-Fe-containing rare earth-iron-nitrogen magnetic powder. The thickness of the R high concentration region can be, for example, 1 nm or more, preferably 3 nm or more and 150 nm or less, more preferably 10 nm or more and 100 nm or less, and even more preferably 20 nm or more and 80 nm or less. The atomic concentration (atomic %) of each element in the R high concentration region is determined by averaging the atomic concentration in the phosphorus compound coating part in STEM-EDX line analysis. The rare earth element (R) may be, for example, Nd, and in that case, the Nd atomic concentration can be evaluated as a high Nd concentration region.
　希土類－鉄－窒素系磁性粉体、水、およびリン含有物を含むスラリーのｐＨを１以上４．５以下の範囲にする調整は、１０分間以上行うことが好ましく、被覆部の厚さが薄い部分を減らす観点から、３０分間以上行うことがより好ましい。ｐＨ維持の初期はｐＨの上昇が早いためにｐＨ制御用の無機酸の投入間隔が短いが、被覆が進むとともに次第にｐＨ変動が緩やかになり、無機酸の投入間隔が長くなることから反応終点が判断できる。 Adjustment of the pH of the slurry containing rare earth-iron-nitrogen magnetic powder, water, and phosphorus-containing material to a range of 1 to 4.5 is preferably carried out for 10 minutes or more, and the thickness of the coating is thin. From the viewpoint of reducing the portion size, it is more preferable to carry out the process for 30 minutes or more. At the beginning of pH maintenance, the pH rises quickly, so the interval of adding inorganic acid for pH control is short, but as the coating progresses, the pH fluctuation gradually becomes gentler, and the interval of adding inorganic acid becomes longer, so that the end point of the reaction can be reached. I can judge.
［リン処理後の酸化工程］
　リン処理工程で得られたリン化合物被覆部を有する希土類－鉄－窒素系磁性粉体を、酸素含有雰囲気下で３５０℃以上６００℃以下で熱処理することにより酸化する。酸化処理により、リン化合物被覆部と希土類－鉄－窒素系磁性粉体の界面から、希土類－鉄－窒素系磁性粉体表面が酸化されて、ナノα－Ｆｅ分離相とＲ酸窒化物相に不均化したα－Ｆｅ含有領域が形成されると考えられる。その結果、高周波領域でのｔａｎδ及び位相角θが向上した磁場増幅用磁性材料及び超高周波領域でのμ”が高い吸収特性を有する磁性材料を得ることができる。
　また、本リン処理後の酸化工程において、リン化合物被覆部より、α－Ｆｅ含有希土類－鉄－窒素系磁性粉体表面上に、酸化鉄が放出され析出する場合がある。リン化合物被覆部が「リン処理後の酸化工程」中にリン酸鉄及び／又はリン酸Ｍと、リン酸希土類の共晶、混晶からリン酸希土類単相に移行していく場合、第１被覆部から余剰の鉄成分が排出されて生ずる現象である。この酸化鉄相は、ヘマタイト、マグネタイト、フェライト、ウスタイトの何れか一種以上であってよいが、この酸化鉄相はヘマタイトである場合が多い。また酸化鉄相はα－Ｆｅ含有希土類－鉄－窒素系磁性粉体表面上に結合されている場合と遊離する場合がある。より優れた効率が求められる用途においては、この酸化鉄相を結合させておくのが好ましく、より高いμ’が求められる用途には遊離させた方がよい。酸化鉄相を遊離させる手段としては、タンブリングなどで機械的に叩き落とす、酸との反応により酸化鉄相のみを溶解させるなどが挙げられる。 [Oxidation step after phosphorus treatment]
The rare earth-iron-nitrogen magnetic powder having the phosphorus compound coating obtained in the phosphorus treatment step is oxidized by heat treatment at 350° C. or higher and 600° C. or lower in an oxygen-containing atmosphere. Through the oxidation treatment, the surface of the rare earth-iron-nitrogen magnetic powder is oxidized from the interface between the phosphorus compound coating and the rare earth-iron-nitrogen magnetic powder, forming a nano α-Fe separated phase and an R oxynitride phase. It is believed that a disproportionate α-Fe-containing region is formed. As a result, it is possible to obtain a magnetic material for magnetic field amplification with improved tan δ and phase angle θ in a high frequency region, and a magnetic material having absorption characteristics with a high μ” in an ultra-high frequency region.
Further, in the oxidation step after the main phosphorus treatment, iron oxide may be released and precipitated from the phosphorus compound coated portion on the surface of the α-Fe-containing rare earth-iron-nitrogen magnetic powder. If the phosphorus compound-coated part transitions from iron phosphate and/or phosphate M and a eutectic or mixed crystal of rare earth phosphate to a single phase of rare earth phosphate during the "oxidation step after phosphorus treatment," This phenomenon occurs when excess iron components are discharged from the coating. This iron oxide phase may be any one or more of hematite, magnetite, ferrite, and wustite, but this iron oxide phase is often hematite. Further, the iron oxide phase may be bonded or free on the surface of the α-Fe-containing rare earth-iron-nitrogen magnetic powder. In applications where better efficiency is required, it is preferable to keep this iron oxide phase bound, whereas in applications where higher μ' is required, it is better to leave it free. Examples of means for liberating the iron oxide phase include mechanically knocking it off by tumbling or the like, and dissolving only the iron oxide phase by reaction with an acid.
　酸化処理は、リン処理後の磁性粉体を、酸素含有雰囲気下で熱処理することにより行う。反応雰囲気は窒素、アルゴンなどの不活性ガス中に酸素を含むことが好ましい。酸素濃度は３体積％以上２１体積％以下が好ましく、３．５体積％以上１０体積％以下がより好ましい。酸化反応中は磁性粉体１ｋｇに対して２Ｌ／分以上１０Ｌ／分以下の流速でガスを交換することが好ましい。 The oxidation treatment is performed by heat-treating the magnetic powder after the phosphorus treatment in an oxygen-containing atmosphere. The reaction atmosphere preferably contains oxygen in an inert gas such as nitrogen or argon. The oxygen concentration is preferably 3 vol% or more and 21 vol% or less, more preferably 3.5 vol% or more and 10 vol% or less. During the oxidation reaction, it is preferable to exchange gas at a flow rate of 2 L/min or more and 10 L/min or less per 1 kg of magnetic powder.
　酸化処理時の温度は３５０℃以上６００℃以下であるが、３８０℃以上５５０℃以下が好ましく、４００℃以上５００℃以下がより好ましく、４２０℃以上４８０℃以下がさらに好ましい。３５０℃未満ではα―Ｆｅ含有領域の生成が不十分であり、高周波領域における比透磁率の実数項が低下する傾向がある。６００℃を超えると磁性粉体が過剰に分解する傾向がある。反応時間は３時間以上１０時間以下が好ましい。 The temperature during the oxidation treatment is 350°C or more and 600°C or less, preferably 380°C or more and 550°C or less, more preferably 400°C or more and 500°C or less, and even more preferably 420°C or more and 480°C or less. If the temperature is lower than 350° C., the formation of the α-Fe-containing region is insufficient, and the real number term of the relative magnetic permeability in the high frequency region tends to decrease. If the temperature exceeds 600°C, the magnetic powder tends to decompose excessively. The reaction time is preferably 3 hours or more and 10 hours or less.
　コア領域の希土類－鉄－窒素系磁性粉体の熱分解温度は約５５０～６５０℃であることが知られている。また、酸素含有雰囲気では、２００℃以上で酸化劣化することも知られている。その中で、酸素を含む雰囲気中、熱分解温度に近い温度まで昇温したのち、優れたα－Ｆｅ含有希土類－鉄－窒素系磁性材料として使用することは、従来知られていなかった。本開示のリン処理により緻密な膜を希土類－鉄－窒素系磁性粉体上に作製したのち、酸素含有雰囲気で熱処理することにより、コア領域を過剰に熱分解させないようにして、リン化合物被覆部下の希土類－鉄－窒素系磁性粉体表面から徐々に不均化反応によりα－Ｆｅをナノレベルでマトリックスから分離、分散させることにより、本発明のα－Ｆｅ含有希土類－鉄－窒素系磁性材料を作製することができると考えられる。このような従来にないプロセスを経て作製した磁性材料が、優れた効率や高いμ’を有することは、全く想到されていなかったことである。 It is known that the thermal decomposition temperature of the rare earth-iron-nitrogen magnetic powder in the core region is about 550 to 650°C. It is also known that in an oxygen-containing atmosphere, oxidative deterioration occurs at temperatures above 200°C. Among these, it has not been previously known that the material can be heated to a temperature close to the thermal decomposition temperature in an oxygen-containing atmosphere and then used as an excellent α-Fe-containing rare earth-iron-nitrogen magnetic material. After a dense film is produced on rare earth-iron-nitrogen magnetic powder by the phosphorus treatment of the present disclosure, heat treatment is performed in an oxygen-containing atmosphere to prevent excessive thermal decomposition of the core region, and to prevent the core region from being thermally decomposed excessively. The α-Fe-containing rare earth-iron-nitrogen magnetic material of the present invention is produced by gradually separating and dispersing α-Fe from the matrix at the nano-level through a disproportionation reaction from the surface of the rare earth-iron-nitrogen magnetic powder. It is thought that it is possible to create It had never been imagined that a magnetic material produced through such an unprecedented process would have excellent efficiency and high μ'.
　α－Ｆｅ含有領域が形成されるメカニズムは、例えば以下のように考えられる。希土類－鉄－窒素粉体表面のリン化合物被覆部や、それと希土類－鉄－窒素粉体との界面を通じて徐々に酸素が供給され、その表面及び／又は界面から希土類－鉄－窒素系材料と酸素との反応（酸化工程）が緩やかに進行することにより、希土類－鉄－窒素系材料はα－Ｆｅ相とＲ酸窒化物相の不均化層に変転し、ナノレベルで相分離した特異な「α－Ｆｅ含有領域」が生じる。このとき、本発明のα－Ｆｅ含有希土類－鉄－窒素系磁性粉体の表面にリン化合物被覆部がなければ、希土類－鉄－窒素系磁性粉体は単に酸化され雰囲気に窒素が散逸することとなり、本発明の場合と比べて急激に反応してしまう。その結果、（１）α－Ｆｅ又は酸化鉄、（２）希土類酸化物、の混合物に変化する。（１）と（２）には格子の整合性がないため、本発明のα－Ｆｅ含有希土類－鉄－窒素系磁性材料のα－Ｆｅ含有領域と異なり、α－Ｆｅの規則的な配列、配向のない不均一な相となりやすい。 The mechanism by which the α-Fe-containing region is formed is thought to be, for example, as follows. Oxygen is gradually supplied through the phosphorus compound coating on the surface of the rare earth-iron-nitrogen powder and the interface between it and the rare-earth-iron-nitrogen powder, and the rare earth-iron-nitrogen material and oxygen are supplied from the surface and/or interface. As the reaction (oxidation process) progresses slowly, the rare earth-iron-nitrogen material transforms into a disproportionate layer of α-Fe phase and R oxynitride phase, resulting in a unique nano-level phase separation. An "α-Fe-containing region" is generated. At this time, if there is no phosphorus compound coating on the surface of the α-Fe-containing rare earth-iron-nitrogen magnetic powder of the present invention, the rare-earth-iron-nitrogen magnetic powder will simply be oxidized and nitrogen will dissipate into the atmosphere. Therefore, the reaction occurs more rapidly than in the case of the present invention. As a result, it changes into a mixture of (1) α-Fe or iron oxide and (2) rare earth oxide. (1) and (2) have no lattice matching, so unlike the α-Fe-containing region of the α-Fe-containing rare earth-iron-nitrogen magnetic material of the present invention, the regular arrangement of α-Fe, It tends to become a non-uniform phase with no orientation.
［シリカ処理工程］
　リン処理工程および酸化工程を経た磁性粉体は、必要に応じてシリカ処理を行ってもよい。磁性粉体にシリカ薄膜を形成することにより、耐酸化性を向上できる。シリカ薄膜は、例えば、アルキルシリケート、磁性粉体、およびアルカリ溶液を混合することにより形成できる。 [Silica treatment process]
The magnetic powder that has undergone the phosphorus treatment step and the oxidation step may be treated with silica if necessary. Oxidation resistance can be improved by forming a silica thin film on magnetic powder. A silica thin film can be formed, for example, by mixing an alkyl silicate, magnetic powder, and an alkaline solution.
［シランカップリング処理工程］
　シリカ処理後の磁性粉体を、さらにシランカップリング剤で処理してもよい。シリカ薄膜が形成された磁性粉体をシランカップリング処理することで、シリカ薄膜上にシランカップリング剤膜が形成され、磁性粉体の磁気特性が向上するとともに、樹脂との濡れ性、成形体の強度を改善することができる。シランカップリング剤は、樹脂の種類に合わせて選定すればよく特に限定されないが、例えば、γ－（２－アミノエチル）アミノプロピルトリメトキシシラン、γ－（２－アミノエチル）アミノプロピルメチルジメトキシシラン、γ－メタクリロキシプロピルトリメトキシシラン、γ－メタクリロキシプロピルメチルジメトキシシラン、Ｎ－β－（Ｎ－ビニルベンジルアミノエチル）－γ－アミノプロピルトリメトキシシラン・塩酸塩、γ－グリシドキシプロピルトリメトキシシラン、γ－メルカプトプロピルトリメトキシシラン、メチルトリメトキシシラン、メチルトリエトキシシラン、ビニルトリアセトキシシラン、γ－クロロプロピルトリメトキシシラン、ヘキサメチレンジシラザン、γ－アニリノプロピルトリメトキシシラン、ビニルトリメトキシシラン、オクタデシル［３－（トリメトキシシリル）プロピル］アンモニウムクロライド、γ－クロロプロピルメチルジメトキシシラン、γ－メルカプトプロピルメチルジメトキシシラン、メチルトリクロロシラン、ジメチルジクロロシラン、トリメチルクロロシラン、ビニルトリクロロシラン、ビニルトリス（βメトキシエトキシ）シラン、ビニルトリエトキシシラン、β－（３，４エポキシシクロヘキシル）エチルトリメトキシシラン、γ－グリシドキシプロピルメチルジエトキシシラン、Ｎ－β（アミノエチル）γ－アミノプロピルトリメトキシシラン、Ｎ－β（アミノエチル）γ－アミノプロピルメチルジメトキシシラン、γ－アミノプロピルトリエトキシシラン、Ｎ－フェニル－γ－アミノプロピルトリメトキシシラン、オレイドプロピルトリエトキシシラン、γ－イソシアネートプロピルトリエトキシシラン、ポリエトキシジメチルシロキサン、ポリエトキシメチルシロキサン、ビス（トリメトキシシリルプロピル）アミン、ビス（３－トリエトキシシリルプロピル）テトラスルファン、γ－イソシアネートプロピルトリメトキシシラン、ビニルメチルジメトキシシラン、１，３，５－Ｎ－トリス（３－トリメトキシシリルプロピル）イソシアヌレート、ｔ－ブチルカルバメートトリアルコキシシラン、Ｎ－（１，３－ジメチルブチリデン）－３－（トリエトキシシリル）－１－プロパンアミン等のシランカップリング剤が挙げられる。これらのシランカップリング剤は１種のみを使用してもよく、２種以上を組み合わせて使用してもよい。シランカップリング剤の添加量は、磁性粉体１００質量部に対して、０．２質量部以上０．８質量部以下が好ましく、０．２５質量部以上０．６質量部以下がより好ましい。０．２質量部未満ではシランカップリング剤の効果が小さく、０．８質量部を超えると、磁性粉体の凝集により、磁性粉体や成形体の磁気特性を低下させる傾向がある。 [Silane coupling treatment process]
The magnetic powder treated with silica may be further treated with a silane coupling agent. By subjecting the magnetic powder on which a silica thin film has been formed to a silane coupling treatment, a silane coupling agent film is formed on the silica thin film, improving the magnetic properties of the magnetic powder, improving wettability with resin, and molding. can improve the strength of The silane coupling agent is not particularly limited as long as it can be selected according to the type of resin, but examples include γ-(2-aminoethyl)aminopropyltrimethoxysilane, γ-(2-aminoethyl)aminopropylmethyldimethoxysilane , γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldimethoxysilane, N-β-(N-vinylbenzylaminoethyl)-γ-aminopropyltrimethoxysilane hydrochloride, γ-glycidoxypropyltri Methoxysilane, γ-mercaptopropyltrimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, vinyltriacetoxysilane, γ-chloropropyltrimethoxysilane, hexamethylenedisilazane, γ-anilinopropyltrimethoxysilane, vinyl trimethoxysilane Methoxysilane, octadecyl[3-(trimethoxysilyl)propyl]ammonium chloride, γ-chloropropylmethyldimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, vinyltrichlorosilane, vinyltris( β-methoxyethoxy)silane, vinyltriethoxysilane, β-(3,4epoxycyclohexyl)ethyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, N-β(aminoethyl)γ-aminopropyltrimethoxysilane , N-β(aminoethyl)γ-aminopropylmethyldimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, oleidopropyltriethoxysilane, γ-isocyanatepropyltriethoxysilane , polyethoxydimethylsiloxane, polyethoxymethylsiloxane, bis(trimethoxysilylpropyl)amine, bis(3-triethoxysilylpropyl)tetrasulfane, γ-isocyanatepropyltrimethoxysilane, vinylmethyldimethoxysilane, 1,3, 5-N-tris(3-trimethoxysilylpropyl)isocyanurate, t-butylcarbamatetrialkoxysilane, N-(1,3-dimethylbutylidene)-3-(triethoxysilyl)-1-propanamine, etc. Examples include silane coupling agents. These silane coupling agents may be used alone or in combination of two or more. The amount of the silane coupling agent added is preferably 0.2 parts by mass or more and 0.8 parts by mass or less, more preferably 0.25 parts by mass or more and 0.6 parts by mass or less, per 100 parts by mass of the magnetic powder. If it is less than 0.2 parts by mass, the effect of the silane coupling agent is small, and if it exceeds 0.8 parts by mass, the magnetic powder tends to agglomerate, resulting in a decrease in the magnetic properties of the magnetic powder or molded body.
　なお、シリカ処理工程、及び／又は、シランカップリング処理工程を行わず、又はこれらの処理工程の後に、イソプロピルトリイソステアロイルチタネート、イソプロピルトリ（Ｎ－アミノエチル－アミノエチル）チタネート、イソプロピルトリス（ジオクチルパイロホスフェート）チタネート、テトライソプロピルビス（ジオクチルホスファイト）チタネート、テトライソプロピルチタネート、テトラブチルチタネート、テトラオクチルビス（ジトリデシルホスファイト）チタネート、イソプロピルトリオクタノイルチタネート、イソプロピルトリドデシルベンゼンスルホニルチタネート、イソプロピルトリ（ジオクチルホスフェート）チタネート、ビス（ジオクチルパイロホスフェート）エチレンチタネート、イソプロピルジメタクリルイソステアロイルチタネート、テトラ（２，２－ジアリルオキシメチル－１－ブチル）ビス（ジトリデシルホスファイト）チタネート、イソプロピルトリクミルフェニルチタネート等のチタン系カップリング剤、アセトアルコキシアルミニウムジイソプロピレートのようなアルミニウム系、ジルコニウム系、クロム系、鉄系、スズ系などのカップリング剤を用いて、磁性粉体の表面処理を行うことができる。この処理を経た粉体をボンド磁性材料とするときは、添加する樹脂との親和性が向上し、α－Ｆｅ含有希土類－鉄－窒素系磁性粉体の孤立分散がより顕著となり、より粉体間の電気的絶縁がなされて、高周波領域での優れた効率や超高周波領域での優れた吸収特性が発現する場合がある。  In addition, isopropyltriisostearoyl titanate, isopropyltri(N-aminoethyl-aminoethyl)titanate, isopropyltris(dioctyl) without performing the silica treatment step and/or the silane coupling treatment step, or after these treatment steps. pyrophosphate) titanate, tetraisopropyl bis(dioctyl phosphite) titanate, tetraisopropyl titanate, tetrabutyl titanate, tetraoctyl bis(ditridecyl phosphite) titanate, isopropyltrioctanoyl titanate, isopropyl tridodecylbenzenesulfonyl titanate, isopropyl tri( Dioctyl phosphate) titanate, bis(dioctyl pyrophosphate) ethylene titanate, isopropyl dimethacrylylisostearoyl titanate, tetra(2,2-diallyloxymethyl-1-butyl) bis(ditridecyl phosphite) titanate, isopropyl tricumylphenyl titanate, etc. The surface of magnetic powder can be treated using titanium-based coupling agents, aluminum-based coupling agents such as acetalkoxyaluminum diisopropylate, zirconium-based, chromium-based, iron-based, tin-based coupling agents, etc. . When the powder that has undergone this treatment is used as a bonded magnetic material, the affinity with the added resin improves, and the isolated dispersion of the α-Fe-containing rare earth-iron-nitrogen magnetic powder becomes more pronounced, making the powder more compact. In some cases, electrical insulation is created between the two, resulting in excellent efficiency in the high frequency range and excellent absorption characteristics in the ultra-high frequency range.​
　リン処理工程後、酸化工程後、シリカ処理工程後、またはシランカップリング処理工程後の磁性粉体は、常法により、ろ過、脱水、乾燥を行うことができる。 After the phosphorus treatment step, the oxidation step, the silica treatment step, or the silane coupling treatment step, the magnetic powder can be filtered, dehydrated, and dried by a conventional method.
　希土類－鉄－窒素系磁性粉体は、粒径の分布を均一化することにより、比透磁率の実数項を向上できる。粒径の分布の均一化は、一般的な乾式分級法や、湿式分級法により行える。粒径の分布の均一化は、リン酸処理前、リン処理工程後、酸化工程後、シリカ処理工程後、シランカップリング処理工程後のいずれの時点で行ってもよい。 The rare earth-iron-nitrogen magnetic powder can improve the real number term of relative magnetic permeability by making the particle size distribution uniform. The particle size distribution can be made uniform by a general dry classification method or a wet classification method. The particle size distribution may be made uniform at any point before the phosphoric acid treatment, after the phosphorus treatment step, after the oxidation step, after the silica treatment step, or after the silane coupling treatment step.
　本実施形態の製造方法で使用する希土類－鉄－窒素系磁性粉体は、Ｒ（ただし、ＲはＹ、Ｃｅ、Ｐｒ、Ｎｄ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｌｕ、Ｓｍの中から選択される少なくとも１種であって、Ｓｍを含む場合は、Ｒ成分全体に対して、Ｓｍが５０原子％未満である）とＦｅ及びＮを含む。Ｒは、Ｙ、Ｃｅ、Ｐｒ、Ｎｄ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｌｕ、Ｓｍの中から選択される少なくとも１種であるが、Ｎｄ、Ｙ、Ｃｅ、Ｐｒ、Ｇｄ、Ｄｙが原料供給の安定性と高い比透磁率の実現の観点から好ましく、さらにＮｄ、Ｙ、Ｃｅ、Ｐｒがコスト面より好ましい。ここで、Ｓｍを含む場合、Ｒ成分全体に対するＳｍの含有量は５０原子％未満であるが、２０原子％未満がより好ましい。特に、Ｎｄ又はＰｒの含有量がＲ成分全体の５０原子％以上であると、より高い比透磁率を有する磁性材料やｔａｎδ及び位相角θがより向上した磁性材料が得られる。さらに、耐酸化性能やコストのバランスから、Ｎｄ又はＰｒの含有量が７０原子％以上であることが好ましく、資源量が豊富で結晶磁気異方性磁場の絶対値（磁気異方性の大きさを示す指標）が大きく、より超高周波での吸収性能が高いことから、Ｎｄの含有量が１００原子％であるＮｄＦｅＮからなる希土類－鉄－窒素系磁性粉体が特に好ましい。 The rare earth-iron-nitrogen magnetic powder used in the manufacturing method of this embodiment is R (where R is Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, Sm). At least one selected from the above, and when Sm is included, Sm is less than 50 atomic % of the entire R component), Fe, and N. R is at least one selected from Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Sm; is preferable from the viewpoint of stability of raw material supply and realization of high relative magnetic permeability, and Nd, Y, Ce, and Pr are more preferable from the viewpoint of cost. Here, when Sm is included, the content of Sm with respect to the entire R component is less than 50 atom %, and more preferably less than 20 atom %. In particular, when the content of Nd or Pr is 50 atomic % or more of the entire R component, a magnetic material having higher relative magnetic permeability and improved tan δ and phase angle θ can be obtained. Furthermore, from the viewpoint of oxidation resistance performance and cost balance, it is preferable that the Nd or Pr content is 70 atomic percent or more, and the absolute value of the magnetocrystalline anisotropy field (the magnitude of the magnetic anisotropy) is A rare earth-iron-nitrogen magnetic powder made of NdFeN with a Nd content of 100 atomic % is particularly preferable because it has a large index (indicating .
　希土類－鉄－窒素系磁性粉体中のＦｅの含有量は、４０原子％以上８７原子％以下が好ましく、５０原子％以上８５原子％以下がより好ましい。 The content of Fe in the rare earth-iron-nitrogen magnetic powder is preferably 40 atomic % or more and 87 atomic % or less, more preferably 50 atomic % or more and 85 atomic % or less.
　以下の実施例などにより、本開示を更に具体的に説明するが、本開示はこれらの実施例などにより何ら限定されるものではない。　 The present disclosure will be explained in more detail with reference to the following examples, but the present disclosure is not limited to these examples in any way.　
　実施例で行った評価方法は以下のとおりである。
（１）元素含有量
　磁性粉体中のＰおよびＭｏの濃度を、ＩＣＰ発光分光分析法（ＩＣＰ－ＡＥＳ　日立ハイテクサイエンス社製ＳＰＳ３５００）を用いて測定した。磁性粉体中のＯおよびＮの濃度は、酸素・窒素分析装置（堀場製作所製ＥＭＧＡ－８２０）を用いて測定した。 The evaluation method performed in the example is as follows.
(1) Elemental Content The concentrations of P and Mo in the magnetic powder were measured using ICP emission spectrometry (ICP-AES SPS3500 manufactured by Hitachi High-Tech Science). The concentrations of O and N in the magnetic powder were measured using an oxygen/nitrogen analyzer (EMGA-820 manufactured by Horiba, Ltd.).
（２）ＸＲＤとα－Ｆｅピーク強度比と半値幅
　磁性粉体について、粉末Ｘ線結晶回折装置（リガク社製、Ｘ線波長：ＣｕＫα）にてＸＲＤパターンを測定した。測定条件は、加速電圧４０ｋＶ、管電流２０ｍＡ、１０＜２θ＜９０の間でステップ幅２θ＝０．０２として行った。ＸＲＤ回折パターンにおいて、α－Ｆｅの（１１０）面の回折ピーク強度（Ｉ）とコア領域の希土類－鉄－窒素系化合物の最強線のピーク強度（ＩＩ）との比（Ｉ）／（ＩＩ）を算出した。（Ｉ）と（ＩＩ）のそれぞれのピークは、２θ＝４４°付近のピークをα－Ｆｅの（１１０）面とし、２θ＝４１．５°のピークを希土類－鉄－窒素系化合物の最強線として、算出した。また、α－Ｆｅの（１１０）面のピークからシェラーの式に用いるピーク半値幅を求めた。 (2) XRD and α-Fe peak intensity ratio and half width The XRD pattern of the magnetic powder was measured using a powder X-ray crystal diffractometer (manufactured by Rigaku Corporation, X-ray wavelength: CuKα). The measurement conditions were an accelerating voltage of 40 kV, a tube current of 20 mA, and a step width of 2θ=0.02 between 10<2θ<90. In the XRD diffraction pattern, the ratio (I)/(II) of the diffraction peak intensity (I) of the (110) plane of α-Fe to the peak intensity (II) of the strongest line of the rare earth-iron-nitrogen compound in the core region was calculated. For each of the peaks of (I) and (II), the peak near 2θ = 44° is the (110) plane of α-Fe, and the peak at 2θ = 41.5° is the strongest line of the rare earth-iron-nitrogen compound. It was calculated as follows. Further, the peak half width used in Scherrer's equation was determined from the peak of the (110) plane of α-Fe.
（３）平均粒径
　磁性粉体の平均粒径は、レーザー回折式粒度分布装置（ＭＡＬＶＥＲＮ　Ｉｎｓｔ．ＭＡＳＴＥＲＳＩＺＥＲ　２０００）を用いて測定した。 (3) Average particle size The average particle size of the magnetic powder was measured using a laser diffraction particle size distribution device (MALVERN Inst. MASTERSIZER 2000).
（４）複素比透磁率測定（１ＭＨｚ～１ＧＨｚ）
　磁性粉体の含有率が９７質量％となるように、磁性粉体と熱硬化性樹脂であるエポキシ樹脂とを混合した後、混練して、樹脂コンパウンドを作製した。この樹脂コンパウンドを内径３．１ｍｍ、外径８ｍｍの金型に仕込んで、加圧力０．８ＧＰａで成形したのち、真空中で１５０℃、２時間熱硬化処理してトロイダル成形体を作製した。この試料を用い、インピーダンスアナライザ（ＨＰ４２９１Ｂ、ヒューレットパッカード社製）により、１ＭＨｚ～１ＧＨｚの周波数範囲の複素比透磁率を、１巻きインダクタ形のテストフィクスチャーより求めたインダクタンス値から評価した。 (4) Complex relative permeability measurement (1MHz to 1GHz)
A resin compound was prepared by mixing the magnetic powder and an epoxy resin, which is a thermosetting resin, so that the content of the magnetic powder was 97% by mass, and then kneading the mixture. This resin compound was charged into a mold with an inner diameter of 3.1 mm and an outer diameter of 8 mm, and was molded with a pressure of 0.8 GPa, followed by heat curing in a vacuum at 150° C. for 2 hours to produce a toroidal molded body. Using this sample, the complex relative magnetic permeability in the frequency range of 1 MHz to 1 GHz was evaluated using an impedance analyzer (HP4291B, manufactured by Hewlett-Packard) based on the inductance value obtained from a single-turn inductor type test fixture.
（５）ＳＴＥＭ－ＥＤＸ分析およびＴＥＭ－ＥＤ分析
　磁性粉体の表面のＳＴＥＭ分析は、以下のようにして行った。まず、得られた磁性粉体を、炭素コーティング後にＦＩＢ（集束イオンビーム）にて断面出しおよび薄片加工を行った。得られたサンプルについて、ＳＴＥＭ（ＦＥＩ社製、型番Ｔａｌｏｓ　Ｆ２００Ｘ；加速電圧２００ｋＶ）とＳＴＥＭに付随したＳＴＥＭ－ＥＤＸ（システム：ＦＥＩ社製、型番ＳｕｐｅｒＸ、検出器：Ｂｒｕｋｅｒ社製ＳＤＤ検出器）を用いて測定した。磁性粉体の外部から内部に向かって後述のステップ幅でライン分析を行い、連続的な各構成元素の原子濃度変化を観測した。この際、測定箇所によっては、断面サンプルの作製に利用した樹脂中の炭素（Ｃ）が、多く検出される箇所が発生するおそれがあるため、Ｃを除いた元素の合計で原子濃度を算出した。また、磁性粉体のα－Ｆｅ含有領域の結晶性および配向性は、ＴＥＭ－ＥＤを用いて評価した。 (5) STEM-EDX analysis and TEM-ED analysis STEM analysis of the surface of the magnetic powder was performed as follows. First, the obtained magnetic powder was coated with carbon and then cross-sectioned and processed into thin pieces using a focused ion beam (FIB). The obtained sample was analyzed using a STEM (manufactured by FEI, model number Talos F200X; acceleration voltage 200 kV) and a STEM-EDX attached to the STEM (system: manufactured by FEI, model number SuperX, detector: SDD detector manufactured by Bruker). It was measured using Line analysis was performed from the outside to the inside of the magnetic powder with the step width described below, and continuous changes in the atomic concentration of each constituent element were observed. At this time, depending on the measurement location, there is a risk that a large amount of carbon (C) in the resin used to prepare the cross-sectional sample may be detected, so the atomic concentration was calculated as the sum of the elements excluding C. . Further, the crystallinity and orientation of the α-Fe-containing region of the magnetic powder were evaluated using TEM-ED.
（６）複素比透磁率測定（１ＧＨｚ～１８ＧＨｚ）
　磁性粉体の含有率が９１．７質量％となるように、磁性粉体と熱可塑性樹脂であるポリアミドエラストマーとを混合、混練した後、ホットプレスを用いて約１ｍｍの厚さの樹脂シートを作製した。この樹脂シートから内径３．０４ｍｍ、外径７ｍｍのトロイダル状の試料を切り出した。この試料を用いて、ネットワークアナライザ（Ｎ５２９０Ａ、キーサイトテクノロジー社製）により、１～１８ＧＨｚの周波数範囲の複素比透磁率を、同軸法により求めたＳパラメーター値から評価した。 (6) Complex relative permeability measurement (1GHz to 18GHz)
After mixing and kneading the magnetic powder and polyamide elastomer, which is a thermoplastic resin, so that the content of the magnetic powder is 91.7% by mass, a resin sheet with a thickness of about 1 mm is formed using a hot press. Created. A toroidal sample having an inner diameter of 3.04 mm and an outer diameter of 7 mm was cut from this resin sheet. Using this sample, the complex relative magnetic permeability in the frequency range of 1 to 18 GHz was evaluated using a network analyzer (N5290A, manufactured by Keysight Technologies) from the S parameter value determined by the coaxial method.
製造例１
　硫酸鉄と硫酸ネオジムを原料とした沈殿法により、以下のようにしてリン処理されていない平均粒径約１５μｍのＮｄ２Ｆｅ１７Ｎ３磁性粉体を作製した。 Manufacturing example 1
By a precipitation method using iron sulfate and neodymium sulfate as raw materials, Nd 2 Fe 17 N 3 magnetic powder having an average particle size of about 15 μm and not subjected to phosphorus treatment was produced as follows.
［Ｎｄ－Ｆｅ硫酸溶液の調製］
　純水２．０ｋｇにＦｅＳＯ４・７Ｈ２Ｏ　５．０ｋｇを混合溶解した。さらにＮｄ２Ｏ３　０．４５ｋｇと７０％硫酸０．７０ｋｇとを加えてよく攪拌し、完全に溶解させた。次に、得られた溶液に純水を加え、最終的にＦｅ濃度が０．７２６ｍｏｌ／Ｌ、Ｎｄ濃度が０．１０６ｍｏｌ／Ｌとなるように調整し、Ｎｄ－Ｆｅ硫酸溶液とした。 [Preparation of Nd-Fe sulfuric acid solution]
5.0 kg of FeSO 4 .7H 2 O was mixed and dissolved in 2.0 kg of pure water. Further, 0.45 kg of Nd 2 O 3 and 0.70 kg of 70% sulfuric acid were added and stirred well to completely dissolve them. Next, pure water was added to the obtained solution to adjust the final Fe concentration to 0.726 mol/L and Nd concentration to 0.106 mol/L, thereby preparing a Nd-Fe sulfuric acid solution.
［沈殿工程］
　温度が４０℃に保たれた純水２０ｋｇ中に、調製したＮｄ－Ｆｅ硫酸溶液全量を反応開始から７０分間で攪拌しながら滴下し、同時に１５％アンモニア水を滴下させ、ｐＨを７～８に調整した。これにより、Ｎｄ－Ｆｅ水酸化物を含むスラリーを得た。得られたスラリーをデカンテーションにより純水で洗浄した後、水酸化物を固液分離した。分離した水酸化物を１００℃のオーブン中で１０時間乾燥した。 [Precipitation process]
The entire amount of the prepared Nd-Fe sulfuric acid solution was added dropwise to 20 kg of pure water kept at a temperature of 40°C while stirring for 70 minutes from the start of the reaction, and at the same time, 15% ammonia water was added dropwise to adjust the pH to 7 to 8. It was adjusted. As a result, a slurry containing Nd--Fe hydroxide was obtained. After washing the obtained slurry with pure water by decantation, the hydroxide was separated into solid and liquid. The separated hydroxide was dried in an oven at 100°C for 10 hours.
［酸化工程］
　沈殿工程で得られた水酸化物を大気中１０３０℃で１時間、焼成処理した。冷却後、原料粉体として赤色のＮｄ－Ｆｅ酸化物を得た。 [Oxidation process]
The hydroxide obtained in the precipitation step was calcined in the air at 1030° C. for 1 hour. After cooling, a red Nd--Fe oxide was obtained as a raw material powder.
［前処理工程］
　Ｎｄ－Ｆｅ酸化物１００ｇを、嵩厚１０ｍｍとなるように鋼製容器に入れた。容器を炉内に入れ、１００Ｐａまで減圧した後、水素ガスを導入しながら、前処理温度の８５０℃まで昇温し、そのまま１５時間保持することにより、黒色粉体の部分酸化物を得た。 [Pre-treatment process]
100 g of Nd--Fe oxide was placed in a steel container so as to have a bulk thickness of 10 mm. After the container was placed in a furnace and the pressure was reduced to 100 Pa, the temperature was raised to the pretreatment temperature of 850° C. while introducing hydrogen gas, and the temperature was maintained for 15 hours to obtain a black powder partial oxide.
［還元工程］
　前処理工程で得られた部分酸化物６０ｇと平均粒径約６ｍｍの金属カルシウム１９．２ｇとを混合して炉内に入れた。炉内を真空排気した後、アルゴンガス（Ａｒガス）を導入した。１０４５℃まで上昇させて、４５分間保持することにより、Ｆｅ－Ｎｄ合金粒子を得た。 [Reduction process]
60 g of the partial oxide obtained in the pretreatment step and 19.2 g of metallic calcium having an average particle size of about 6 mm were mixed and placed in a furnace. After the inside of the furnace was evacuated, argon gas (Ar gas) was introduced. By raising the temperature to 1045°C and holding it for 45 minutes, Fe--Nd alloy particles were obtained.
［窒化工程］
　引き続き、炉内温度を１００℃まで冷却した後、真空排気を行い、窒素ガスを導入しながら、温度を４５０℃まで上昇させて、そのまま２３時間保持して、磁性粉体を含む塊状生成物を得た。 [Nitriding process]
Subsequently, after cooling the temperature inside the furnace to 100°C, the furnace was evacuated, and while nitrogen gas was introduced, the temperature was raised to 450°C and held for 23 hours to remove the lumpy product containing magnetic powder. Obtained.
［水洗工程］
　窒化工程で得られた塊状の生成物を純水３ｋｇに投入し、３０分間攪拌した。静置した後、デカンテーションにより上澄みを排水した。純水への投入、攪拌及びデカンテーションを１０回繰り返した。次いで９９．９％酢酸２．５ｇを投入して１５分間攪拌した。静置した後、デカンテーションにより上澄みを排水した。純水への投入、攪拌及びデカンテーションを２回繰り返し行い、続いて脱水と乾燥後、機械的解砕処理を行うことでＮｄ２Ｆｅ１７Ｎ３磁性粉体（平均粒径約１５μｍ）を得た。 [Water washing process]
The lumpy product obtained in the nitriding step was poured into 3 kg of pure water and stirred for 30 minutes. After standing still, the supernatant was drained by decantation. Adding to pure water, stirring and decantation were repeated 10 times. Next, 2.5 g of 99.9% acetic acid was added and stirred for 15 minutes. After standing still, the supernatant was drained by decantation. Adding to pure water, stirring and decantation were repeated twice, followed by dehydration and drying, followed by mechanical crushing to obtain Nd 2 Fe 17 N 3 magnetic powder (average particle size of about 15 μm). Ta.
比較例１
　製造例１で作製したＮｄ２Ｆｅ１７Ｎ３磁性粉体を用いて、以下のようにリン処理した。リン酸処理液として、８５％オルトリン酸：リン酸二水素ナトリウム：モリブデン酸ナトリウム２水和物＝１：６：１の質量比で混合し、純水と希塩酸でｐＨを２、ＰＯ４濃度を２０質量％に調整したものを準備した。水洗工程で得られたＮｄ－Ｆｅ－Ｎ系磁性粉体を、水１０００ｇ：塩化水素７０ｇの希塩酸中で１分間攪拌して表面酸化膜や汚れ成分を除去した後、上澄み液の導電率が１００μＳ／ｃｍ以下になるまで排水と注水を繰り返し、Ｎｄ－Ｆｅ－Ｎ系異方性磁性粉体を１０質量％含むスラリーを得た。得られたスラリーを撹拌しながら、準備したリン酸処理液１００ｇを処理槽中に全量投入した後、６質量％の塩酸を随時投入することでリン酸処理反応スラリーのｐＨを２．０±０．１の範囲にて制御し４０分間維持した。続いて吸引濾過、脱水し、真空乾燥することでリン化合物被覆部を有するＮｄ－Ｆｅ－Ｎ系異方性磁性粉体を得た。 Comparative example 1
The Nd 2 Fe 17 N 3 magnetic powder produced in Production Example 1 was subjected to phosphorus treatment as follows. As a phosphoric acid treatment solution, mix 85% orthophosphoric acid: sodium dihydrogen phosphate: sodium molybdate dihydrate at a mass ratio of 1:6:1, adjust the pH to 2 with pure water and dilute hydrochloric acid, and adjust the PO 4 concentration. A sample adjusted to 20% by mass was prepared. The Nd-Fe-N magnetic powder obtained in the water washing process was stirred for 1 minute in dilute hydrochloric acid containing 1000 g of water and 70 g of hydrogen chloride to remove the surface oxide film and dirt components, and the conductivity of the supernatant liquid was 100 μS. Drainage and water injection were repeated until the concentration of the powder was reduced to less than /cm to obtain a slurry containing 10% by mass of Nd--Fe--N anisotropic magnetic powder. While stirring the obtained slurry, the entire amount of 100 g of the prepared phosphoric acid treatment solution was added into the treatment tank, and then 6% by mass of hydrochloric acid was added at any time to adjust the pH of the phosphoric acid treatment reaction slurry to 2.0±0. The temperature was controlled within a range of .1 and maintained for 40 minutes. Subsequently, the powder was suction-filtered, dehydrated, and vacuum-dried to obtain an anisotropic Nd--Fe--N magnetic powder having a phosphorus compound coating.
実施例１～４、比較例２～３
　比較例１のリン化合物被覆部を有するＮｄ－Ｆｅ－Ｎ系異方性磁性粉体３００ｇを、窒素とエアーの混合ガス（酸素濃度４体積％、５Ｌ／ｍｉｎ）雰囲気下で室温から徐々に昇温し、表１に記載の最高温度で８時間の熱処理を実施し、酸化処理された実施例１及び２の希土類－鉄－窒素系磁性粉体（平均粒径約１５μｍ）を得た。 Examples 1 to 4, Comparative Examples 2 to 3
300 g of the Nd-Fe-N anisotropic magnetic powder having a phosphorus compound coating of Comparative Example 1 was heated gradually from room temperature in an atmosphere of a mixed gas of nitrogen and air (oxygen concentration 4% by volume, 5 L/min). Then, heat treatment was carried out for 8 hours at the maximum temperature listed in Table 1 to obtain oxidized rare earth-iron-nitrogen magnetic powders (average particle size of about 15 μm) of Examples 1 and 2.
　比較例１と同様にして得た平均粒径約１３μｍのリン化合物被覆部を有するＮｄ－Ｆｅ－Ｎ系異方性磁性粉体を用い、実施例１及び２と同様にして表１に記載の最高温度で８時間の熱処理を実施して、酸化処理された実施例３及び４、比較例２及び３の希土類－鉄－窒素系磁性粉体（平均粒径は表１に示す）を得た。 Using the Nd-Fe-N anisotropic magnetic powder having a phosphorus compound coated part with an average particle diameter of about 13 μm obtained in the same manner as in Comparative Example 1, the powders listed in Table 1 were prepared in the same manner as in Examples 1 and 2. Heat treatment was performed at the maximum temperature for 8 hours to obtain oxidized rare earth-iron-nitrogen magnetic powders of Examples 3 and 4 and Comparative Examples 2 and 3 (average particle diameters are shown in Table 1). .
　実施例１～４及び比較例１～３で作製した磁性粉体を使用して、前述した方法でＰ、Ｍｏ、Ｏ、Ｎの各元素含有量、α－Ｆｅピーク強度比を測定した。リン処理後の酸化温度、平均粒径とともに、測定結果を表１に示す。また、実施例１～４及び比較例１～３で作製した磁性粉体のＸＲＤパターンを図１に示す。 Using the magnetic powders produced in Examples 1 to 4 and Comparative Examples 1 to 3, the content of each element of P, Mo, O, and N and α-Fe peak intensity ratio were measured by the method described above. The measurement results are shown in Table 1 along with the oxidation temperature and average particle size after the phosphorus treatment. Further, the XRD patterns of the magnetic powders produced in Examples 1 to 4 and Comparative Examples 1 to 3 are shown in FIG.
　表１より、磁性粉体中の酸素Ｏの含有量は、３２０℃までの処理温度ではほとんど変化がない。これは、リン化合物被覆部の存在により磁性粉体の酸化が抑制されていることを示している。また、３５０℃以上の処理温度では次第にＯが増大し、同時にα－Ｆｅのブロードなピーク強度が上昇し始める。これは、３５０℃以上の処理温度でＲ酸窒化物相とナノサイズのα－Ｆｅが生成し始め、α－Ｆｅ含有領域が形成され始めることを示している。また、３８０℃からはヘマタイトの回折ピークが成長し始め、リン化合物被覆部の外側に酸化鉄層が形成されることが考えられる。 From Table 1, the content of oxygen O in the magnetic powder hardly changes at processing temperatures up to 320°C. This indicates that the presence of the phosphorus compound coating suppresses oxidation of the magnetic powder. Further, at a treatment temperature of 350° C. or higher, O gradually increases and at the same time, the broad peak intensity of α-Fe begins to increase. This indicates that at a processing temperature of 350° C. or higher, the R oxynitride phase and nano-sized α-Fe begin to be generated, and an α-Fe-containing region begins to be formed. Further, it is considered that the diffraction peak of hematite starts to grow from 380° C., and an iron oxide layer is formed on the outside of the phosphorus compound coating.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　比較例１（図２Ａ及び図２Ｂ）、実施例１（図３Ａ及び３Ｂ）、実施例２（図４Ａ及び４Ｂ、図５Ａ及び５Ｂ）、および実施例４（図６Ａ及び６Ｂ、図７Ａ及び７Ｂ、図８）の磁性粉体表面付近のＳＴＥＭ、ＥＤＸ、ＴＥＭおよびＥＤ像を観測した。実施例２のみＳＴＥＭ（日本電子社製、型番ＪＥＭ－Ｆ２００；加速電圧２００ｋＶ）とＳＴＥＭに付随したＳＴＥＭ－ＥＤＸ（システム：日本電子社製、型番ＳＤ１００ＨＲ、検出器：日本電子社製ドライＳＤ検出器）で観察した。各ＳＴＥＭ、ＥＤＸ、ＴＥＭにおいて、それぞれ５３０９００倍（図２Ａ）、６４００００倍（図３Ａ）、２５０００００倍（図４Ａ）、２５００００倍（図５Ａ）、３２００００倍（図６Ａ）、１４０００倍（図７Ａ）、７４０００倍（図８）で観察した。得られたＳＴＥＭ像、ＳＴＥＭ―ＥＤＸ像およびライン分析結果を、それぞれ図２～図７に示す。各ライン分析におけるステップ幅はそれぞれ０．１８ｎｍ（図２Ｂ）、０．１８ｎｍ（図３Ｂ）、０．１６ｎｍ（図４Ｂ）、１．６ｎｍ（図５Ｂ）、０．３６ｎｍ（図６Ｂ）、８．２ｎｍ（図７Ｂ）である。 Comparative Example 1 (FIGS. 2A and 2B), Example 1 (FIGS. 3A and 3B), Example 2 (FIGS. 4A and 4B, FIGS. 5A and 5B), and Example 4 (FIGS. 6A and 6B, FIGS. 7A and 7B) , Fig. 8), STEM, EDX, TEM, and ED images near the surface of the magnetic powder were observed. Example 2 only STEM (manufactured by JEOL Ltd., model number JEM-F200; acceleration voltage 200 kV) and STEM-EDX attached to STEM (system: manufactured by JEOL Ltd., model number SD100HR, detector: dry SD detector manufactured by JEOL Ltd.) ) was observed. For each STEM, EDX, and TEM, 530,900 times (Fig. 2A), 640,000 times (Fig. 3A), 2,500,000 times (Fig. 4A), 250,000 times (Fig. 5A), 320,000 times (Fig. 6A), and 14,000 times (Fig. 7A) , observed at 74,000x (Figure 8). The obtained STEM image, STEM-EDX image, and line analysis results are shown in FIGS. 2 to 7, respectively. The step widths in each line analysis were 0.18 nm (Figure 2B), 0.18 nm (Figure 3B), 0.16 nm (Figure 4B), 1.6 nm (Figure 5B), 0.36 nm (Figure 6B), and 8. 2 nm (FIG. 7B).
　図２Ａ（比較例１）より、リン化合物被覆部の内側には母材であるコア領域のみが存在すると考えられる。また、図３Ａ（実施例１）、図４Ａ（実施例２）、図６Ａ（実施例４）では被膜の内側に、ナノサイズのＦｅおよびＮｄを含む相が生成していることが観測された。また、図４ＡのＳＴＥＭ―ＥＤＸ像において、ＦｅもしくはＮｄに注目した際に、α－Ｆｅ含有領域で海－島構造のコントラストが観測され、「海」及び「島」の各領域付近の元素の組成比を測定したところ、「島」領域付近では、「海」領域付近に比べて、Ｆｅの含有組成比が高く、ＮｄおよびＯの含有組成比が小さくなっていることが確認された。また、図３Ａのα－Ｆｅ含有領域の拡大図を図１０に示す。図１０のＡｒｅａ１と、Ａｒｅａ２におけるＮ、Ｏ、Ｆｅ、Ｎｄの原子濃度を表２に示す。 From FIG. 2A (Comparative Example 1), it is thought that only the core region, which is the base material, exists inside the phosphorus compound coating portion. Furthermore, in Figure 3A (Example 1), Figure 4A (Example 2), and Figure 6A (Example 4), it was observed that a phase containing nano-sized Fe and Nd was generated inside the coating. . In addition, in the STEM-EDX image in Figure 4A, when focusing on Fe or Nd, a sea-island structure contrast was observed in the α-Fe-containing region, and the contrast of the elements near the "sea" and "island" regions was observed. When the composition ratio was measured, it was confirmed that near the "island" region, the content composition ratio of Fe was higher and the content composition ratio of Nd and O was lower than near the "sea" region. Further, FIG. 10 shows an enlarged view of the α-Fe-containing region in FIG. 3A. Table 2 shows the atomic concentrations of N, O, Fe, and Nd in Area 1 and Area 2 in FIG. 10.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表２に示すように、Ａｒｅａ２ではＡｒｅａ１よりもＮｄ、Ｎ、Ｏが多く検出され、Ａｒｅａ１ではＦｅが多く検出された。この結果およびＸＲＤ結果より、Ｆｅを多く含む層はα－Ｆｅ相であり、Ｎｄを多く含む領域は、酸化ネオジム、窒化ネオジム、または酸窒化ネオジムを含む相であると推測される。なお、薄片試料の厚さ（約１００ｎｍ）にあたる深さ方向の情報が平均化されることや、試料中での電子線の散乱のため、α－Ｆｅ相においてもＮ、Ｏ、Ｎｄが検出され、酸化ネオジム、窒化ネオジム、または酸窒化ネオジムを含む相においてもＦｅが検出されたと考えられる。このことから図３Ａの構造においても、Ｆｅと比較してＮｄの方に酸素などが多く含まれ、Ｒ酸化物相（もしくはＲ酸窒化物相）という形で「島」領域であるＡｒｅａ１が存在しており、同時にＦｅが多く含まれる、「海」領域であるＡｒｅａ２が存在していると推測される。図３Ｂ（実施例１）、図４Ｂ（実施例２）、図６Ｂ（実施例４）から、実施例１、２および４では、被膜として、リン化合物や酸化鉄層が含まれていると考えられる。 As shown in Table 2, more Nd, N, and O were detected in Area 2 than in Area 1, and more Fe was detected in Area 1. From this result and the XRD result, it is estimated that the layer containing a large amount of Fe is an α-Fe phase, and the region containing a large amount of Nd is a phase containing neodymium oxide, neodymium nitride, or neodymium oxynitride. Note that N, O, and Nd are also detected in the α-Fe phase because the information in the depth direction corresponding to the thickness of the thin sample (approximately 100 nm) is averaged and because the electron beam is scattered in the sample. It is thought that Fe was also detected in phases containing neodymium oxide, neodymium nitride, or neodymium oxynitride. Therefore, in the structure shown in Figure 3A, Nd contains more oxygen than Fe, and Area 1, which is an "island" region, exists in the form of R oxide phase (or R oxynitride phase). At the same time, it is presumed that Area 2, which is a "sea" region that contains a large amount of Fe, exists. From FIG. 3B (Example 1), FIG. 4B (Example 2), and FIG. 6B (Example 4), it is thought that Examples 1, 2, and 4 contain a phosphorus compound or an iron oxide layer as a coating. It will be done.
　ＳＴＥＭ―ＥＤＸ分析およびＸＲＤパターンより、ナノサイズのＦｅはα－Ｆｅであることが推測され、ＳＴＥＭ－ＥＤＸおよびライン分析結果よりＮｄを含む相はＯおよびＮを含む（Ｒ酸窒化物相）と推測される。また、ナノサイズのα－ＦｅおよびＲ酸窒化物相は実施例４で大きくなっていた。α－Ｆｅを含む領域の膜厚は約２０ｎｍ（実施例１）、約４００ｎｍ（実施例２）、約４μｍ（実施例４）であった。また、実施例２および実施例４の表面付近とα－Ｆｅ含有領域全体のライン分析結果（図４Ｂ、図５Ｂ、図６Ｂ、図７Ｂ）において、最表面付近および各相の界面のプロファイル形状が異なるが、ライン分析におけるステップ幅の違いによるものである。また、実施例４においては、ＸＲＤパターンの２θ＝２３°、３３°付近にペロブスカイト構造のＮｄＦｅＯ３と推測されるブロードなピークが観測された。 From the STEM-EDX analysis and the XRD pattern, it is inferred that nano-sized Fe is α-Fe, and from the STEM-EDX and line analysis results, the phase containing Nd contains O and N (R oxynitride phase). Guessed. Furthermore, the nano-sized α-Fe and R oxynitride phases were larger in Example 4. The film thickness of the region containing α-Fe was approximately 20 nm (Example 1), approximately 400 nm (Example 2), and approximately 4 μm (Example 4). In addition, in the line analysis results near the surface and the entire α-Fe-containing region in Examples 2 and 4 (Fig. 4B, Fig. 5B, Fig. 6B, Fig. 7B), the profile shape near the outermost surface and at the interface of each phase is The difference is due to the difference in step width in line analysis. Furthermore, in Example 4, broad peaks, which are presumed to be NdFeO 3 having a perovskite structure, were observed near 2θ=23° and 33° in the XRD pattern.
　図８に実施例４のα－Ｆｅ含有領域のＳＴＥＭ像および電子線回折像を示す。図８右図は、［１１１］入射による、図８左図に示した直径２００ｎｍ円の領域内のα－Ｆｅの電子線回折像である。図８右図の、内側の輝度の高い六角形の回折点はα－Ｆｅの｛１１０｝に帰属される。この部分のα－Ｆｅ相の大きさは１０ｎｍ以下で均質に配列されていることがＥＤＸ像解析から（図６Ａ参照）推測され、図８左図に鮮明なスポットが観察されていることから、直径２００ｎｍの範囲でα－Ｆｅ相は一方向に配列、配向していることが考えられる。しかし、それ以外にも輝度の薄いサテライトが、原点、α－Ｆｅ由来の｛１１０｝及び｛２２０｝の回折点間に等間隔で観察されている。これはα－Ｆｅ相を取り囲む、α－Ｆｅに格子整合したＲ酸窒化物相由来の回折点と考えられ、α－Ｆｅ含有領域が２００ｎｍの範囲内で、α－Ｆｅ相、Ｒ酸窒化物のマトリックス相ともに結晶化して配列、配向していることを指し示している。このような整然とした構造が形成されることで、電気的絶縁と磁気的連結を高度に両立させた磁性粉体となると考えられる。 FIG. 8 shows a STEM image and an electron diffraction image of the α-Fe-containing region of Example 4. The right figure in FIG. 8 is an electron beam diffraction image of α-Fe within the 200 nm diameter circle region shown in the left figure in FIG. 8 due to [111] incidence. The inner hexagonal diffraction point with high brightness in the right diagram of FIG. 8 is assigned to {110} of α-Fe. It is estimated from EDX image analysis (see Figure 6A) that the size of the α-Fe phase in this part is 10 nm or less and is uniformly arranged, and a clear spot is observed in the left diagram of Figure 8. It is considered that the α-Fe phase is aligned and oriented in one direction within a diameter range of 200 nm. However, other satellites with low brightness are observed at equal intervals between the origin and the {110} and {220} diffraction points derived from α-Fe. This is considered to be a diffraction point derived from the R oxynitride phase that surrounds the α-Fe phase and is lattice matched to α-Fe. This indicates that both the matrix phase of the material is crystallized, aligned, and oriented. It is thought that the formation of such an orderly structure results in a magnetic powder that achieves both electrical insulation and magnetic connection to a high degree.
　また、図１のＸＲＤパターンにおけるα－Ｆｅの（１１０）面のピークから、シェラーの式に従い、それぞれの結晶子径を算出した（６．８ｎｍ（実施例１）、８．７ｎｍ（実施例２）、８．９ｎｍ（実施例３）、８．６ｎｍ（実施例４））。ＳＴＥＭ―ＥＤＸにより観察された粒径よりも大きく算出されたが、α－Ｆｅ相だけでなく一部で格子整合した希土類酸化物も含む結晶として回折ピークに現れた可能性が考えられる。 In addition, the respective crystallite diameters were calculated from the peak of the (110) plane of α-Fe in the XRD pattern of FIG. ), 8.9 nm (Example 3), 8.6 nm (Example 4)). Although the grain size was calculated to be larger than that observed by STEM-EDX, it is possible that the grain size appeared in the diffraction peak as a crystal containing not only the α-Fe phase but also a portion of the lattice-matched rare earth oxide.
　比較例１～３、実施例１～４の磁性粉体を用い、前述した方法で１ＭＨｚ～１ＧＨｚにおける複素比透磁率測定用試料をそれぞれ作製した（密度５．８５（比較例１）、５．３８（比較例２）、５．５４（比較例３）、５．６６（実施例１）、５．２７（実施例２）、５．４０（実施例３）、４．９７（実施例４）のトロイダル成形体（樹脂添加量６質量％））。前述した方法で１ＭＨｚ～１００ＭＨｚの複素比透磁率の周波数依存性を測定した結果を図９に示し、高周波特性の評価結果を表３に示す。　 Using the magnetic powders of Comparative Examples 1 to 3 and Examples 1 to 4, samples for complex relative permeability measurement at 1 MHz to 1 GHz were prepared by the method described above (density 5.85 (Comparative Example 1), 5. 38 (Comparative Example 2), 5.54 (Comparative Example 3), 5.66 (Example 1), 5.27 (Example 2), 5.40 (Example 3), 4.97 (Example 4) ) toroidal molded body (resin addition amount: 6% by mass)). The results of measuring the frequency dependence of complex relative magnetic permeability from 1 MHz to 100 MHz using the method described above are shown in FIG. 9, and the evaluation results of high frequency characteristics are shown in Table 3.　
　比較例１～３ではθ１／θ２が０．７未満であったが、実施例１～４ではθ１／θ２が０．８以上であった。これは、リン処理後の酸化工程によってα－Ｆｅ含有領域が生成され、電気的絶縁性が高まったためと考えられる。また、実施例２、実施例３では、比較例１～３よりも低密度でありながらμ’は向上していた。これは、リン処理後の酸化工程によってα－Ｆｅ含有領域が生成され、磁気的連結の効果が大きくなったためと考えられる。さらに、実施例１～４は１３ＭＨｚでのθが８５°以上（ｔａｎδが０．０８７５以下）であり、損失が低く、ＲＦＩＤのアンテナ材料として好適に用いることができるが、比較例１～３では、θが８５°未満（ｔａｎδが０．０８７５を超える）と損失が高く、効率が低かった。 In Comparative Examples 1 to 3, θ 1 /θ 2 was less than 0.7, but in Examples 1 to 4, θ 1 /θ 2 was 0.8 or more. This is considered to be because an α-Fe-containing region is generated by the oxidation step after the phosphorus treatment, and the electrical insulation is improved. Further, in Examples 2 and 3, μ' was improved even though the density was lower than that in Comparative Examples 1 to 3. This is considered to be because α-Fe-containing regions are generated by the oxidation step after the phosphorus treatment, increasing the effect of magnetic coupling. Furthermore, in Examples 1 to 4, θ at 13 MHz is 85° or more (tan δ is 0.0875 or less), and the loss is low and can be suitably used as an RFID antenna material, but in Comparative Examples 1 to 3, , when θ was less than 85° (tan δ exceeded 0.0875), the loss was high and the efficiency was low.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
実施例５及び比較例４
　比較例１と同様にして得た磁性粉体を分級することで、平均粒径約４μｍのリン処理した希土類－鉄－窒素系磁性粉体を作製した（比較例４）。また、実施例１と同様にして得た磁性粉体を分級することで、平均粒径約４μｍのα－Ｆｅ含有希土類－鉄－窒素系磁性粉体を作製した（実施例５）。比較例４および実施例５の平均粒径の測定には、レーザー回折式粒度分布測定装置（日本レーザー株式会社製　ＨＥＬＯＳ＆ＲＯＤＯＳ）を用いた。それぞれ密度約５．０ｇ／ｃｍ３の樹脂シートを作製して、１ＧＨｚ、７．６ＧＨｚ（実施例５のμ”が極大値を取る周波数）、１０ＧＨｚのμ”の値を評価し、その結果を表４に示した。１～１０ＧＨｚの領域で、実施例５の磁性材料では、比較例４に比べて高いμ”を示した。 Example 5 and comparative example 4
By classifying the magnetic powder obtained in the same manner as in Comparative Example 1, a phosphorus-treated rare earth-iron-nitrogen magnetic powder having an average particle size of about 4 μm was produced (Comparative Example 4). Further, by classifying the magnetic powder obtained in the same manner as in Example 1, α-Fe-containing rare earth-iron-nitrogen magnetic powder with an average particle size of about 4 μm was produced (Example 5). The average particle diameters of Comparative Example 4 and Example 5 were measured using a laser diffraction particle size distribution analyzer (HELOS&RODOS, manufactured by Nippon Laser Co., Ltd.). Resin sheets each having a density of approximately 5.0 g/cm 3 were prepared, and the values of μ'' at 1 GHz, 7.6 GHz (the frequency at which μ'' in Example 5 takes the maximum value), and 10 GHz were evaluated, and the results were evaluated. It is shown in Table 4. In the region of 1 to 10 GHz, the magnetic material of Example 5 showed a higher μ'' than Comparative Example 4.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
実施例６
　実施例２と同様にして得た磁性粉体を分級することで、平均粒径約１７μｍのα－Ｆｅ含有希土類－鉄－窒素系磁性粉体を作製した。平均粒径の測定には、レーザー回折式粒度分布測定装置（日本レーザー株式会社製　ＨＥＬＯＳ＆ＲＯＤＯＳ）を用いた。実施例１～４と同様の方法で樹脂と混合してトロイダル成形体（密度５．５８）を作製し、インピーダンスアナライザを用いて、１ＭＨｚ～１ＧＨｚの周波数範囲の複素比透磁率を、１巻きインダクタ形のテストフィクスチャーより求めたインダクタンス値から評価した。その結果を表５に示した。また、表５において実施例２の結果も再掲した。前述した方法で１ＭＨｚ～１００ＭＨｚの複素比透磁率の周波数依存性を測定した結果を図１１に示した。分級を行った実施例６の磁性粉体は、実施例２と比べて高いμ’を示した。 Example 6
By classifying the magnetic powder obtained in the same manner as in Example 2, α-Fe-containing rare earth-iron-nitrogen magnetic powder with an average particle size of about 17 μm was produced. A laser diffraction particle size distribution analyzer (HELOS&RODOS, manufactured by Nippon Laser Co., Ltd.) was used to measure the average particle size. A toroidal molded body (density 5.58) was prepared by mixing with resin in the same manner as in Examples 1 to 4, and using an impedance analyzer, the complex relative magnetic permeability in the frequency range of 1 MHz to 1 GHz was measured using a one-turn inductor. Evaluation was made from the inductance value obtained from a shaped test fixture. The results are shown in Table 5. In addition, the results of Example 2 are also listed in Table 5. FIG. 11 shows the results of measuring the frequency dependence of complex relative magnetic permeability from 1 MHz to 100 MHz using the method described above. The magnetic powder of Example 6, which was classified, showed a higher μ' than that of Example 2.
Figure JPOXMLDOC01-appb-T000005
Figure JPOXMLDOC01-appb-T000005
　本開示にかかる発明は、例えば以下の態様を包含してよい。
［１］希土類Ｒ（ＲはＹ、Ｃｅ、Ｐｒ、Ｎｄ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｌｕ、およびＳｍからなる群から選択される少なくとも１種であって、Ｓｍを含む場合はＲ成分全体に対してＳｍが５０原子％未満である）、Ｆｅ、およびＮを含むコア領域と、前記コア領域の外側に、α－Ｆｅ、ならびに前記希土類Ｒの酸化物、窒化物、および酸窒化物からなる群から選択される少なくとも１種を含むα－Ｆｅ含有領域とを有する、α－Ｆｅ含有希土類－鉄－窒素系磁性粉体。 The invention according to the present disclosure may include, for example, the following aspects.
[1] Rare earth R (R is at least one selected from the group consisting of Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Sm, and includes Sm (Sm is less than 50 atomic % based on the entire R component), a core region containing Fe, and N, and outside the core region, α-Fe, and an oxide, nitride, and α-Fe-containing rare earth-iron-nitrogen-based magnetic powder having an α-Fe-containing region containing at least one member selected from the group consisting of oxynitrides.
［２］前記α－Ｆｅ含有領域は前記希土類Ｒの酸化物、窒化物、および酸窒化物からなる群から選択される少なくとも１種からなるナノ結晶、ならびにα－Ｆｅからなるナノ結晶を含む、［１］に記載のα－Ｆｅ含有希土類－鉄－窒素系磁性粉体。 [2] The α-Fe-containing region includes nanocrystals made of at least one selected from the group consisting of oxides, nitrides, and oxynitrides of the rare earth R, and nanocrystals made of α-Fe. α-Fe-containing rare earth-iron-nitrogen magnetic powder according to [1].
［３］前記α－Ｆｅ含有領域の厚みが、前記α－Ｆｅ含有希土類－鉄－窒素系磁性粉体の平均粒径の０．０１％以上５０％未満である、［１］または［２］に記載のα－Ｆｅ含有希土類－鉄－窒素系磁性粉体。 [3] The thickness of the α-Fe-containing region is 0.01% or more and less than 50% of the average particle size of the α-Fe-containing rare earth-iron-nitrogen magnetic powder, [1] or [2] α-Fe-containing rare earth-iron-nitrogen magnetic powder described in .
［４］前記α－Ｆｅ含有領域の厚みが、１ｎｍ以上１０μｍ以下である、［１］～［３］のいずれかに記載のα－Ｆｅ含有希土類－鉄－窒素系磁性粉体。 [4] The α-Fe-containing rare earth-iron-nitrogen magnetic powder according to any one of [1] to [3], wherein the thickness of the α-Fe-containing region is 1 nm or more and 10 μm or less.
［５］前記コア領域は、希土類－鉄－窒素系化合物を含み、ＸＲＤ回折パターンにおいて、α－Ｆｅの（１１０）面の回折ピーク強度（Ｉ）と前記希土類－鉄－窒素系化合物の最強線のピーク強度（ＩＩ）との比（Ｉ）／（ＩＩ）が０．０１以上１０未満である、［１］～［４］のいずれかに記載のα－Ｆｅ含有希土類－鉄－窒素系磁性粉体。 [5] The core region contains a rare earth-iron-nitrogen compound, and in the XRD diffraction pattern, the diffraction peak intensity (I) of the (110) plane of α-Fe and the strongest line of the rare earth-iron-nitrogen compound The α-Fe-containing rare earth-iron-nitrogen magnetism according to any one of [1] to [4], wherein the ratio (I)/(II) to the peak intensity (II) of is 0.01 or more and less than 10. powder.
［６］１０ＭＨｚでの比透磁率の実数項が６以上である、［１］～［５］のいずれかに記載のα－Ｆｅ含有希土類－鉄－窒素系磁性粉体。 [6] The α-Fe-containing rare earth-iron-nitrogen magnetic powder according to any one of [1] to [5], wherein the real number term of relative magnetic permeability at 10 MHz is 6 or more.
［７］１００ＭＨｚでの位相角をθ１とし、２ＭＨｚでの位相角をθ２としたとき、θ１／θ２が０．８以上である、［１］～［６］のいずれかに記載のα－Ｆｅ含有希土類－鉄－窒素系磁性粉体。 [7] Any one of [1] to [6], where θ 1 /θ 2 is 0.8 or more, where the phase angle at 100 MHz is θ 1 and the phase angle at 2 MHz is θ 2. α-Fe-containing rare earth-iron-nitrogen magnetic powder.
［８］１３ＭＨｚでの位相角θが８５°以上である、［１］～［７］のいずれかに記載のα－Ｆｅ含有希土類－鉄－窒素系磁性粉体。 [8] The α-Fe-containing rare earth-iron-nitrogen magnetic powder according to any one of [1] to [7], which has a phase angle θ of 85° or more at 13 MHz.
［９］［１］～［８］のいずれかに記載のα－Ｆｅ含有希土類－鉄－窒素系磁性粉体を含む、磁場増幅用磁性材料。 [9] A magnetic material for magnetic field amplification, comprising the α-Fe-containing rare earth-iron-nitrogen magnetic powder according to any one of [1] to [8].
［１０］さらに樹脂を含む、［９］に記載の磁場増幅用磁性材料。 [10] The magnetic material for magnetic field amplification according to [9], further comprising a resin.
［１１］無線給電に用いられる［９］または［１０］に記載の磁場増幅用磁性材料。 [11] The magnetic material for magnetic field amplification according to [9] or [10], which is used for wireless power supply.
［１２］［１］～［８］のいずれかに記載のα－Ｆｅ含有希土類－鉄－窒素系磁性粉体を含む、超高周波吸収用磁性材料。 [12] A magnetic material for ultra-high frequency absorption, comprising the α-Fe-containing rare earth-iron-nitrogen magnetic powder according to any one of [1] to [8].
［１３］希土類Ｒ（ＲはＹ、Ｃｅ、Ｐｒ、Ｎｄ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｌｕ、およびＳｍからなる群から選択される少なくとも１種であって、Ｓｍを含む場合はＲ成分全体に対してＳｍが５０原子％未満である）、Ｆｅ、およびＮを含むコア領域と、前記コア領域の外側に、海領域および島領域を含む海－島構造を有し、Ｆｅの原子濃度（％）は島領域の方が海領域よりも高く、希土類ＲおよびＯの原子濃度（％）は島領域の方が海領域よりも低い、α－Ｆｅ含有領域とを有する、α－Ｆｅ含有希土類－鉄－窒素系磁性粉体。 [13] Rare earth R (R is at least one selected from the group consisting of Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Sm, and includes Sm has a sea-island structure including a core region containing Fe and N, and a sea region and an island region outside the core region; The atomic concentration (%) of is higher in the island region than in the sea region, and the atomic concentration (%) of rare earths R and O is lower in the island region than in the sea region. -Fe-containing rare earth-iron-nitrogen magnetic powder.
［１４］希土類Ｒ（ＲはＹ、Ｃｅ、Ｐｒ、Ｎｄ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｌｕ、およびＳｍからなる群から選択される少なくとも１種であって、Ｓｍを含む場合はＲ成分全体に対してＳｍが５０原子％未満である）、Ｆｅ、およびＮを含む希土類－鉄－窒素系磁性粉体、水、ならびにリン含有物を含むスラリーに対して無機酸を添加することで、希土類－鉄－窒素系磁性粉体上にリン化合物被覆部を形成して、リン化合物被覆部を有する希土類－鉄－窒素系磁性粉体を得るリン処理工程、および前記リン化合物被覆部を有する希土類－鉄－窒素系磁性粉体を、酸素含有雰囲気下で３５０℃以上６００℃以下で熱処理する酸化工程を含むα－Ｆｅ含有希土類－鉄－窒素系磁性粉体の製造方法。 [14] Rare earth R (R is at least one selected from the group consisting of Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Sm, and includes Sm An inorganic acid is added to a slurry containing a rare earth-iron-nitrogen magnetic powder containing Sm (based on the entire R component), Fe, and N, water, and a phosphorus-containing material. A phosphorus treatment step of forming a phosphorus compound coating portion on the rare earth-iron-nitrogen magnetic powder to obtain a rare earth-iron-nitrogen magnetic powder having the phosphorus compound coating portion; A method for producing α-Fe-containing rare earth-iron-nitrogen magnetic powder, comprising an oxidation step of heat-treating rare earth-iron-nitrogen magnetic powder having the following:
［１５］前記リン処理工程において、前記無機酸を添加して、前記スラリーのｐＨを１以上４．５以下に調整する［１４］に記載のα－Ｆｅ含有希土類－鉄－窒素系磁性粉体の製造方法。 [15] The α-Fe-containing rare earth-iron-nitrogen magnetic powder according to [14], wherein in the phosphorus treatment step, the inorganic acid is added to adjust the pH of the slurry to 1 or more and 4.5 or less. manufacturing method.
　本開示によれば、優れた磁場増幅特性及び超高周波吸収特性を有するα－Ｆｅ含有希土類－鉄－窒素系磁性粉体が得られる。この磁性粉体は、磁場増幅用磁性材料及び超高周波吸収用磁性材料として好適に使用することができる。この磁場増幅用磁性材料及び超高周波吸収用磁性材料は、主として動力機器や情報通信関連機器に用いられる、高周波または超高周波領域で使用されるトランス、ヘッド、インダクタ、リアクトル、コア（磁芯）、ヨーク、ＲＦＩＤタグや無線給電などの高周波や超高周波を送受信する素子やアンテナに用いられる材料、マイクロ波素子、磁歪素子、磁気音響素子及び磁気記録素子など、ホール素子、磁気センサ、電流センサ、回転センサ、電子コンパスなどの磁場を介したセンサ類に用いられる磁性材料、さらに電磁ノイズ吸収材料、電磁波吸収材料や磁気シールド用材料などの不要な電磁波干渉による障害を抑制する磁性材料、ノイズ除去用インダクタなどのインダクタ素子用材料又はノイズフィルタ用材料などの高周波または超高周波領域で信号からノイズを除去する磁性材料などに使用することができる。 According to the present disclosure, α-Fe-containing rare earth-iron-nitrogen magnetic powder having excellent magnetic field amplification characteristics and ultra-high frequency absorption characteristics can be obtained. This magnetic powder can be suitably used as a magnetic material for magnetic field amplification and a magnetic material for ultrahigh frequency absorption. These magnetic materials for magnetic field amplification and ultra-high frequency absorption magnetic materials are mainly used in power equipment and information communication related equipment, such as transformers, heads, inductors, reactors, cores (magnetic cores) used in high frequency or ultra-high frequency regions, Materials used in yokes, elements and antennas that transmit and receive high frequencies and ultra-high frequencies such as RFID tags and wireless power supply, microwave elements, magnetostrictive elements, magnetoacoustic elements and magnetic recording elements, Hall elements, magnetic sensors, current sensors, rotation Magnetic materials used in sensors, electronic compasses, and other sensors that use a magnetic field; magnetic materials that suppress interference caused by unnecessary electromagnetic interference, such as electromagnetic noise absorbing materials, electromagnetic wave absorbing materials, and magnetic shielding materials; and noise-eliminating inductors. It can be used for magnetic materials that remove noise from signals in high frequency or ultra-high frequency regions, such as materials for inductor elements or materials for noise filters.

Claims (15)

  1. 希土類Ｒ（ＲはＹ、Ｃｅ、Ｐｒ、Ｎｄ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｌｕ、およびＳｍからなる群から選択される少なくとも１種であって、Ｓｍを含む場合はＲ成分全体に対してＳｍが５０原子％未満である）、Ｆｅ、およびＮを含むコア領域と、
    前記コア領域の外側に、α－Ｆｅ、ならびに前記希土類Ｒの酸化物、窒化物、および酸窒化物からなる群から選択される少なくとも１種を含むα－Ｆｅ含有領域とを有する、
    α－Ｆｅ含有希土類－鉄－窒素系磁性粉体。     Rare earth R (R is at least one selected from the group consisting of Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Sm, and when Sm is included, the R component a core region containing Sm (less than 50 atomic % of the total), Fe, and N;
    outside the core region, an α-Fe-containing region containing α-Fe and at least one selected from the group consisting of oxides, nitrides, and oxynitrides of the rare earth R;
    Rare earth-iron-nitrogen magnetic powder containing α-Fe.
  2. 前記α－Ｆｅ含有領域は、
    前記希土類Ｒの酸化物、窒化物、および酸窒化物からなる群から選択される少なくとも１種からなるナノ結晶、ならびに
    α－Ｆｅからなるナノ結晶を含む、
    請求項１に記載のα－Ｆｅ含有希土類－鉄－窒素系磁性粉体。     The α-Fe containing region is
    Nanocrystals made of at least one selected from the group consisting of oxides, nitrides, and oxynitrides of the rare earth R, and nanocrystals made of α-Fe.
    The α-Fe-containing rare earth-iron-nitrogen magnetic powder according to claim 1.
  3. 前記α－Ｆｅ含有領域の厚みが、前記α－Ｆｅ含有希土類－鉄－窒素系磁性粉体の平均粒径の０．０１％以上５０％未満である、
    請求項１または２に記載のα－Ｆｅ含有希土類－鉄－窒素系磁性粉体。     The thickness of the α-Fe-containing region is 0.01% or more and less than 50% of the average particle size of the α-Fe-containing rare earth-iron-nitrogen magnetic powder.
    The α-Fe-containing rare earth-iron-nitrogen magnetic powder according to claim 1 or 2.
  4. 前記α－Ｆｅ含有領域の厚みが、１ｎｍ以上１０μｍ以下である、
    請求項１から３のいずれか１項に記載のα－Ｆｅ含有希土類－鉄－窒素系磁性粉体。     The thickness of the α-Fe containing region is 1 nm or more and 10 μm or less,
    The α-Fe-containing rare earth-iron-nitrogen magnetic powder according to any one of claims 1 to 3.
  5. 前記コア領域は、希土類－鉄－窒素系化合物を含み、
    ＸＲＤ回折パターンにおいて、α－Ｆｅの（１１０）面の回折ピーク強度（Ｉ）と前記希土類－鉄－窒素系化合物の最強線のピーク強度（ＩＩ）との比（Ｉ）／（ＩＩ）が０．０１以上１０未満である、請求項１から４のいずれか１項に記載のα－Ｆｅ含有希土類－鉄－窒素系磁性粉体。     The core region includes a rare earth-iron-nitrogen compound,
    In the XRD diffraction pattern, the ratio (I)/(II) between the diffraction peak intensity (I) of the (110) plane of α-Fe and the peak intensity (II) of the strongest line of the rare earth-iron-nitrogen compound is 0. The α-Fe-containing rare earth-iron-nitrogen magnetic powder according to any one of claims 1 to 4, wherein the α-Fe-containing rare earth-iron-nitrogen magnetic powder is .01 or more and less than 10.
  6. １０ＭＨｚでの比透磁率の実数項が６以上である、請求項１から５のいずれか１項に記載のα－Ｆｅ含有希土類－鉄－窒素系磁性粉体。 The α-Fe-containing rare earth-iron-nitrogen magnetic powder according to claim 1, wherein the real number term of relative magnetic permeability at 10 MHz is 6 or more.
  7. １００ＭＨｚでの位相角をθ１とし、２ＭＨｚでの位相角をθ２としたとき、θ１／θ２が０．８以上である、請求項１から６のいずれか１項に記載のα－Ｆｅ含有希土類－鉄－窒素系磁性粉体。 The α- according to any one of claims 1 to 6, wherein θ 1 /θ 2 is 0.8 or more, where the phase angle at 100 MHz is θ 1 and the phase angle at 2 MHz is θ 2. Fe-containing rare earth-iron-nitrogen magnetic powder.
  8. １３ＭＨｚでの位相角θが８５°以上である、請求項１から７のいずれか１項に記載のα－Ｆｅ含有希土類－鉄－窒素系磁性粉体。 The α-Fe-containing rare earth-iron-nitrogen magnetic powder according to claim 1, wherein the phase angle θ at 13 MHz is 85° or more.
  9. 請求項１から８のいずれか１項に記載のα－Ｆｅ含有希土類－鉄－窒素系磁性粉体を含む、磁場増幅用磁性材料。 A magnetic material for magnetic field amplification, comprising the α-Fe-containing rare earth-iron-nitrogen magnetic powder according to any one of claims 1 to 8.
  10. さらに樹脂を含む、請求項９に記載の磁場増幅用磁性材料。 The magnetic material for magnetic field amplification according to claim 9, further comprising a resin.
  11. 無線給電に用いられる請求項９または１０に記載の磁場増幅用磁性材料。 The magnetic material for magnetic field amplification according to claim 9 or 10, which is used for wireless power supply.
  12. 請求項１から８のいずれか１項に記載のα－Ｆｅ含有希土類－鉄－窒素系磁性粉体を含む、超高周波吸収用磁性材料。 A magnetic material for ultra-high frequency absorption, comprising the α-Fe-containing rare earth-iron-nitrogen magnetic powder according to any one of claims 1 to 8.
  13. 希土類Ｒ（ＲはＹ、Ｃｅ、Ｐｒ、Ｎｄ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｌｕ、およびＳｍからなる群から選択される少なくとも１種であって、Ｓｍを含む場合はＲ成分全体に対してＳｍが５０原子％未満である）、Ｆｅ、およびＮを含むコア領域と、
    前記コア領域の外側に、海領域および島領域を含む海－島構造を有し、Ｆｅの原子濃度（％）は島領域の方が海領域よりも高く、希土類ＲおよびＯの原子濃度（％）は島領域の方が海領域よりも低い、α－Ｆｅ含有領域とを有する、
    α－Ｆｅ含有希土類－鉄－窒素系磁性粉体。     Rare earth R (R is at least one selected from the group consisting of Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Sm, and when Sm is included, the R component a core region containing Sm (less than 50 atomic % of the total), Fe, and N;
    It has a sea-island structure including a sea region and an island region outside the core region, and the atomic concentration (%) of Fe is higher in the island region than in the sea region, and the atomic concentration (%) of rare earths R and O is higher in the island region than in the sea region. ) has a lower α-Fe content region in the island region than in the sea region,
    Rare earth-iron-nitrogen magnetic powder containing α-Fe.
  14. 希土類Ｒ（ＲはＹ、Ｃｅ、Ｐｒ、Ｎｄ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｌｕ、およびＳｍからなる群から選択される少なくとも１種であって、Ｓｍを含む場合はＲ成分全体に対してＳｍが５０原子％未満である）、Ｆｅ、およびＮを含む希土類－鉄－窒素系磁性粉体、水、ならびにリン含有物を含むスラリーに対して無機酸を添加することで、希土類－鉄－窒素系磁性粉体上にリン化合物被覆部を形成して、リン化合物被覆部を有する希土類－鉄－窒素系磁性粉体を得るリン処理工程、および
    前記リン化合物被覆部を有する希土類－鉄－窒素系磁性粉体を、酸素含有雰囲気下で３５０℃以上６００℃以下で熱処理する酸化工程
    を含むα－Ｆｅ含有希土類－鉄－窒素系磁性粉体の製造方法。     Rare earth R (R is at least one selected from the group consisting of Y, Ce, Pr, Nd, Gd, Tb, Dy, Ho, Er, Tm, Lu, and Sm, and when Sm is included, the R component By adding an inorganic acid to a slurry containing rare earth-iron-nitrogen magnetic powder containing Sm (less than 50 atomic % of the total), Fe, and N, water, and a phosphorus-containing material, A phosphorus treatment step of forming a phosphorus compound coating on a rare earth-iron-nitrogen magnetic powder to obtain a rare earth-iron-nitrogen magnetic powder having a phosphorus compound coating, and a rare earth metal having the phosphorus compound coating. - A method for producing an α-Fe-containing rare earth-iron-nitrogen magnetic powder, which includes an oxidation step of heat-treating the iron-nitrogen magnetic powder at a temperature of 350° C. or higher and 600° C. or lower in an oxygen-containing atmosphere.
  15. 前記リン処理工程において、前記無機酸を添加して、前記スラリーのｐＨを１以上４．５以下に調整する請求項１４に記載のα－Ｆｅ含有希土類－鉄－窒素系磁性粉体の製造方法。
          The method for producing α-Fe-containing rare earth-iron-nitrogen magnetic powder according to claim 14, wherein in the phosphorus treatment step, the inorganic acid is added to adjust the pH of the slurry to 1 or more and 4.5 or less. .
PCT/JP2023/029295 2022-08-19 2023-08-10 α-FE-CONTAINING RARE EARTH ELEMENT-IRON-NITROGEN MAGNETIC POWDER, MANUFACTURING METHOD FOR SAME, MAGNETIC MATERIAL FOR MAGNETIC FIELD AMPLIFICATION, AND MAGNETIC MATERIAL FOR ULTRA-HIGH FREQUENCY ABSORPTION WO2024038829A1 (en)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004146542A (en) * 2002-10-23 2004-05-20 Asahi Kasei Chemicals Corp Solid material for magnet and its manufacturing method
JP2018127716A (en) * 2017-02-06 2018-08-16 国立大学法人東北大学 Rare-earth-iron-nitrogen based magnetic powder and method for producing the same
JP2021105192A (en) * 2019-12-26 2021-07-26 国立大学法人東北大学 Rare earth-iron-nitrogen magnetic powder, bond magnet compound, bond magnet, and method for producing rare earth-iron-nitrogen magnetic powder
JP2022010511A (en) * 2020-06-29 2022-01-17 国立大学法人東北大学 Rare earth-iron-nitrogen based magnetic powder, compound for bond magnet, bond magnet and method for producing rare earth-iron-nitrogen based magnetic powder
JP2022080817A (en) * 2020-11-18 2022-05-30 日亜化学工業株式会社 Method for manufacturing compound for bond magnet

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004146542A (en) * 2002-10-23 2004-05-20 Asahi Kasei Chemicals Corp Solid material for magnet and its manufacturing method
JP2018127716A (en) * 2017-02-06 2018-08-16 国立大学法人東北大学 Rare-earth-iron-nitrogen based magnetic powder and method for producing the same
JP2021105192A (en) * 2019-12-26 2021-07-26 国立大学法人東北大学 Rare earth-iron-nitrogen magnetic powder, bond magnet compound, bond magnet, and method for producing rare earth-iron-nitrogen magnetic powder
JP2022010511A (en) * 2020-06-29 2022-01-17 国立大学法人東北大学 Rare earth-iron-nitrogen based magnetic powder, compound for bond magnet, bond magnet and method for producing rare earth-iron-nitrogen based magnetic powder
JP2022080817A (en) * 2020-11-18 2022-05-30 日亜化学工業株式会社 Method for manufacturing compound for bond magnet

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